"We are arriving later."
Translation:Wir kommen später an.
What particles can be separated from the verb in German?
I mean you have "ausehen" which means to look , to semble "Ich sehe nicht cool aus" I don't look cool. And you have "verkaufen" which means to sell, but technically it's ver+ kaufen(to buy). and you don't separate it "Ich verkaufe dir einen Hemd" I sell you a shirt
Is there a list of words that can be separated?
The rule of thumb is that a verb has a separable prefix if it is stressed on the prefix, while the prefix is not separable if the stress is on the verb stem.
AUSsehen has the stress on the first syllable while verKAUFen has the stress on the second syllable.
It's also not possible to create a list of prefixes which are always separable, as verbs that have such syllable are not always stressed on the prefix. For example, the word spelled umfahren is actually two words: UMfahren (to run over, to driver over something and knock it down: separable) and umFAHRen (to drive around something, to swerve to avoid something: inseparable). So you can't make a rule that "um = separable" or "um = inseparable" because it depends on the verb stress.
The correct stress of a verb is something you have to learn, more or less like the gender of nouns.
That said, there are some prefixes which are always inseparable, because they are never stressed; these include be- ver- ent- zer- mis- er-.
"Wir kommen später an" sollte auch akzeptiert werden.
That is accepted and is even the default/"best" translation.
Do you have a screenshot of that sentence being rejected? If so, please share it with us -- upload it to a website somewhere such as imgur and put the URL of the image in a comment here.
Otherwise I'm going to guess that you made a mistake. (Prove me wrong.)