—Did you call on any of your old friends when you returned to your hometown?—_______ of them. They were all very busy.

Good health is __________ most people take for granted--- until they lose it .

The real test of ______ English is whether they can speak, read, write and orally understand good standard English.

The old lady is said to have three children，two of ____studying abroad.

The world’s elderly population will exceed(超过) ____ of children by 2060, when each group ____ to account for about one fifth of the population.