Let's discuss non-English usages/forms for Esperanto
Much of the difficulty in learning any foreign language is the need to not only learn the grammar and vocabulary, but how things are stated or phrased.
I propose we use this thread to list usages that differ between the two languages.
"By" is often replaced with "de" in Esperanto:
En: I read a book by William Auld.
Eo: Mi legis libron de William Auld.
Referring to age:
En: He is 3 years old.
Eo: Li aĝas 3 jarojn. (Literally "He ages/is aged 3 years")
Big one: English progressive tenses are not usually rendered with the progressive tense in Esperanto.
I am reading a book = Mi legas libron. (Many beginning students try things like "Mi estas legas libron" or "Mi estas legi libron", which are wrong... slightly more advanced ones might use "Mi estas leganta libron" which is not wrong but not common unless you really want to emphasise the on-going nature of the action.)
Number agreement is a bit different in the case where you have two adjectives modifying the same noun or two nouns modified by the same adjective.
If you have a grey cat and a black cat, then that would be "I have a grey and a black cat" in English but "Mi havas grizan kaj nigran katojn" in Esperanto: plural noun but singular adjectives. Plural noun because there are two cats, but singular adjectives because there is only one grey one and one black one.
Conversely, "His new house and garden" would be "Liaj novaj domo kaj ĝardeno" with plural adjectives (because he has two new things) but singular nouns (because there is only one house and one garden).
The construction "kiel eble plej X" for "as X as possible" is a bit unusual from an English point of view.
Time agreement is different in Esperanto and English in reported speech and other subordinate clauses.
"He said he was writing a letter" = Li diris, ke li skribas leteron. (Compare: "He said: 'I am writing a letter'." His exact quote uses the present tense, and Esperanto does so even in reported speech.)
Jen aliaj kutimaj mallongigoj: http://bertilow.com/pmeg/aldonoj/simboloj_mallongigoj.html.
Here's one from "Being Colloquial in Esperanto" by David Jordan (http://pages.ucsd.edu/~dkjordan/eo/colloq/colloq042.html#sec4-3-1)- Note that instead of a participle, the infinitive is used:<pre>
Legi stultajn romanojn estas bone. = Reading stupid novels is good. Vidi stultajn filmojn estas pli bone. = Seeing stupid films is better. Labori dek horojn sinsekve ĉe la komputilo estas blindige. = Working ten hours together at the computer is blinding</pre>
"Legante stultajn romanojn estas bone" does not make sense.
What may be confusing you is that the English -ing form merges two forms that used to be distinct: the present participle and the gerund.
-ant- in Esperanto is only the present participle; but only the gerund makes sense here.