It was from the earliest time（）men began to study the natural phenomena and heavenly bodies.

It（）his father（）made him a lawyer.

It is（）that should be given priority to.

It was（）it raised many difficult questions that the book took a long time to come out.

It was the color of the material（）he was surprised at.

His mother had talked to him for two hours while he was watching TV, but（）.

—We have to stop talking here. Listen, （）! —Hurry up, or we’ll be late.

She didn’t come to the party last Sunday. （）, she must have made the party more exciting.

I received his mother’s telephone call at eleven.（）that he was badly hurt in an accident yesterday.

—The old man wouldn’t stay at home for a rest even if it rained. —（）. He would feel sick if he stayed home for one day.