Scientists ______ thousands of chemicals before they decided on the right one in the end.
He picked up an envelope ____50 dollars in it.
The husband rushed to the hospital ____ he heard that his wife was injured.
At the shopping centre, he didn’t know what _____ and _____ with an empty bag.
A few people were killed in the fire, but _____ were saved.
—You went late _______ the stadium yesterday evening, didn’t you? —Yes, my wife was a little late _______ the supper.