Modern science and technology has _____ communication between people far apart.
______ you understand this rule, you’ll have no further difficulty.
It will not be long _____man can harness the solar energy and make it serve mankind.
Doing your homework is a sure way to improve your test scores, and this is especially true______ it comes to the classroom tests.
Substances will expand or contract ______ heated or cooled, but this is not the case with water.
You can arrive in Beijing earlier for the meeting __ you don’t mind taking the night train.