_____ of water makes Death Valley a desert, but it is by no means devoid.
-What did you do yesterday afternoon? -I went to the bookstore,___ some books and visited my uncle.
The stone on the river bank rolled under her feet; she was _____into the river,and she called out for help.
-Everyone says you are a good student. You are never late for school,are you? -_______.
_____ all the inventions have in common is ______ they have succeeded.
Last term our maths teacher set so difficult an examination problem _____ none of us worked out.