It was in the lab_________was taken charge of by Johnson_________they did the experiment.
—Good morning. Can I help you? —I’d like to have this package ________.
—Do you rememberhe came? —Yes, of course. He came by train.
Although my parents are very busy, they still ______ a lot of time to us.
Remember ______ the book when you have finished it.
I need one more stamp before my collection______.