Help keep them focused.

Make sure they're reading the directions.

Make sure they don't use a translator.

Explain the directions to them.

Ask them questions about what they're doing.

Point them to where they can get the answer.

Explain the concept to them.

Quiz them on their vocabulary.

Help them with technology.

tell them the answers.

correct their work for them (although you can tell them which ones are wrong and give them hints as to why they are wrong... just don't give them the correct answer).

translate words for them or tell them how to say something.  The vocabulary from the class/book is sufficient for what they are being asked to do.  Refer them back to the book or their notes.  If they have to work for it, they will remember it.