In the US, students can do almost anythingthey want in class, ____ they don’t make too much noise or disturb others whowant to learn from the teacher.

sult is not very important to us, but if we dowin, then so much _______.

You can only be sure of _____ you have at present; you cannot be sure of something _____ you might get in the future.

We have been told that under no circumstances ______ the telephone in the office for personal affairs.

The fact has worried many scientists_______ the earth is becoming warmer and warmer these days.