Translation:I doubt that he can work in this hot weather.
My great discovery to share is this link...I hope it works...copy paste if not. We DO use the subjunctive a lot in English after certain verbs and words listed on this site and we just are not conscious of it. The link needs to be shared for as people tackle the subjunctive since it throws a lot of people.
Technically, if you say "work with this heat," it means that you are working with the heat itself. So, it really is a better translation to say "work in this heat." However, it is true that colloquially many English-speakers use "with [fill in the blank]" to reference a longer nominative phrase. For instance, they might also say "I doubt he can work with this noise," but what he really means is: "I doubt he can work with this noise [going on]." It is the missing words that are likely cause the confusion here.
I think if you were talking about heat you are currently experiencing you should say "this", however if you're talking about heat you are not experiencing at the moment you're speaking (i.e. you're indoors or at a different time or place) you should say "that" but depending on the situation "with" may or may not be acceptable and when it is not "in" is the best solution. This is because "with this..." is a colloquialism (i.e. "I can't focus with this noise", "He can't get anything done with this rain" or "He can't do his job with these storms".)
As far as a pattern I'd say "with" is only acceptable if what your talking about is directly affecting (usually only hindering) you or whoever your talking about. I would say it is most common when talking about weather so with this/that heat is a good English translation.
You're right that there are no grammar notes for the subjunctive units, which is a shame because those are pretty important and it isn't necessarily obvious to native English speakers, since we don't really go in for subjunctive very much. Although the Duo folks are very busy, I hope and trust that there will be grammar notes for this stuff eventually.
The subjunctive stem "puiss-" for the verb pouvoir is found in Lesson 1 of the 3 lessons in the Subjunctive Present unit. It's irregular (obviously!) and we are meant to slap the appropriate ending onto it.
Here's a quick overview of present subjunctive, including the basics, if anyone is interested. This is going to get VERY LONG, so no one should read beyond this point if they are already comfortable with subjunctive or simply aren't really that interested. :-)
"Indicative mood" refers to when verbs are used in statements of fact, and "subjunctive mood" refers to when there is some kind of uncertainty or opinion involved. "I can speak French" is a statement of fact. "It is useful that I can speak French" is a statement of opinion. "He doesn't believe that I can speak French" is a statement of doubt/uncertainty. "We shouldn't go to France unless one of us can speak French" is a statement of opinion too.
The most common use of subjunctives is when your sentence has two clauses with two different subjects (actors), connected by "que" (usually equivalent to "that" in English). Taking one of the example sentences from the paragraph above, "He doesn't believe that I can speak French" has two clauses - he doesn't believe, and I can speak French. "He" is the subject of the first clause and "I" am the subject of the second clause. "That" ("que") connects the two clauses.
Most present subjunctives are formed by taking the third person plural form of the present tense, cutting off the ending, and adding the subjunctive endings -e, -es, -e, -ions, -iez, -ent (for je, tu, il/elle, nous, vous, ils/elles respectively). What this means is that many of your "-er" verbs are going to end up looking exactly the same in the subjunctive as they do in the normal present (indicative), EXCEPT for the nous and vous conjugations, because those endings are different than the usual present tense endings.
So let's take a nice regular verb like parler as an example. Our present indicative third person plural is "parlent." We remove the "-ent" to get the stem "parl-" and then add our endings as follows:
Il est impossible que je parle japonais. (First clause has impersonal subject "il" meaning "it" instead of "he" in this case. Second clause has subject "je." Two different subjects, clauses joined by "que." Requires subjunctive. BUT compare to the indicative statement "Je parle japonais." You can see that it's "parle" either way, indicative or subjunctive, so it looks and sounds the same in subjunctive or indicative.)
Il est impossible que tu parles japonais.
Il est impossible qu'elle parle japonais.
Il est impossible que nous parlions japonais. (Notice that this looks different than the indicative statement "Nous parlons japonais" would look.)
Il est impossible que vous parliez japonais. (Ditto.)
Il est impossible qu'elles parlent japonais. (And we're back to normal, here.)
For "-re" and "-ir" verbs, the third person plural in subjunctive will still look like normal present indicative, but the other conjugations will tend to look different. Let's use vivre as an example. Third person plural = "vivent." Remove the "-ent" ending to get the stem "viv-" and then add our endings:
Mes parents veulent que je vive avec eux. (Compare to the indicative statement, Je vis avec eux. So "vive" and "vis" are distinguishable.)
Tes parents veulent que tu vives avec eux.
Ses parents veulent qu'il vive avec eux.
Nos parents veulent que nous vivions avec eux.
Vos parents veulent que vous viviez avec eux.
Leurs parents veulent qu'ils vivent avec eux. (This verb form looks the same, whether subjunctive or indicative.)
How about finir? You start with "ils finissent," remove "-ent" to get stem "finiss-" and then add the endings:
Il faut que je finisse mes devoirs. (Compare to the indicative statement, Je finis mes devoirs. So "finisse" and "finis" are distinguishable.)
Il faut que tu finisses tes devoirs.
Il faut qu'elle finisse ses devoirs.
Il faut que nous finissions nos devoirs.
Il faut que vous finissiez vos devoirs.
Il faut qu'ils finissent leurs devoirs. (This verb form looks the same, whether subjunctive or indicative.)
Some of the more common irregular stems are, of course, some of the more commonly used verbs overall. Examples:
Pouvoir becomes puiss- plus endings, as we have seen.
Faire becomes fass- plus endings (Il faut que nous fassions attention!)
And of course avoir, aller, and être are just completely irregular, because we use them all the time and why would they be simple and normal, right?!
avoir: que j'aie, que tu aies, qu'il/elle ait, que nous ayons, que vous ayez, qu'ils/elles aient
aller: que j'aille, que tu ailles, qu'il/elle aille, que nous allions (note stem change!), que vous alliez, qu'ils/elles aillent
être: que je sois, que tu sois, qu'il/elle soit, que nous soyons, que vous soyez, qu'ils/elles soient
There is no future subjunctive - we use present subjunctive for anything referring to now or in the future. There is a past subjunctive, which is the forms of avoir or être conjugated appropriately, plus the past participle. "Il était nécessaire que je sois allée au bureau," for example. It was necessary = an opinion. As opposed to the indicative "Je suis allée au bureau" (a statement of fact: I went to the office).
Remember that you can usually get around the subjunctive if you aren't sure whether it ought to be used in a specific situation. For example, regarding the supposed necessity of my having had to go to the office at some point in the past (see paragraph above), I could have got around using the subjunctive by saying "Il m'était nécessaire d'aller au bureau," perhaps, or "J'ai dû aller au bureau." In either of those work-arounds, we don't have two clauses with two different subjects connected by "que."
Finally, if you have borne with me thus far, please note that there are also imperfect and pluperfect subjunctive moods, but you won't hear them spoken, nor will you have to speak them. They are literary and you will probably be able to recognize them when you see them, most likely in older and/or more formal written texts. Don't worry about them.
Thanks so much for this super lesson! Three lingots for taking the time. I also thought I should point out that after I did the first of the set of subj. lessons, clicking on conjugate began to show the subjunctive forms in the chart, which it didn't before. Maybe its a minor glitch but I'm pretty sure the same thing happened with future tense before, conjugate doesn't update until after completing the first lesson - I'm sure Duo will tweak that in time.
I really wonder if French speakers actually use all these tenses when speaking... if so that's quite impressive! I would assume learning to spell correctly would be more of an academic pursuit, but even the relatively easier verbal conjugation is pretty intensive.
"Cet homme est tres chaleureux. Quand nous parlons, il est tres gentil. Mais ici, tout le monde est tres mechant. S'il travaillait ici avec nous, je doute qu'il pouvait travailler avec cette chaleur." So: "I doubt that he could work with such cordiality/geniality/sincerity/enthusiasm."