en has three children, one of whom isa child of six, ___ twins of twelve.

Each boy and each girltalking about optional courses（选修课）.—Yes! And the eachtheir favorite one!

______should be allowed to choose their clothes.

The two scientists have discovered 65 0f the more than 100 planets ________orbiting other stars [ ]

It was yesterday _____I went to the railway station to meet my uncle. ( )