—Remember that where and when two different English question words___________. —I see, but can you tell us how to use them, sir?

______ without friends ______ the most difficult challenge for Chuck while living on the island.

It’s 8 o’clock. The students _________ an English class.

Many sheep _______ eating grass by the river.

The number of people invited ______ fifty, but a number of them ____ absent for different reasons.