You’d better look up the new word in a dictionary____ you don’t know it.

The traffic rules say drivers mustn’t drive if they are drunk, _______they will be punished.

I arrived at the airport ________ the plane had taken off.

—We’ll visit the Summer Palace_____ there is a heavy rain tomorrow. — OK! Boating on the lake must be great fun.

 We won’t start the meeting ___ our teacher arrives.