—How can I use the equipment?—Well, just refer to the ________.
21.It was not until dark ____ he found ____ he thought was the correct way to slove the problem.
20.—Though it is 30 years _____ we last met, I still remember the scene _____ we got separated on a rainy day.
19.—My cat’s really fat. —You ______ have given her so much food.
18.—Jim, are you ______ this Saturday?—Oh, sorry. I need to go to the bookshop _____ the bank on Saturday.
17.I _______there little more than a week when I set to work with the scientist.