—Did you see the film star?—________，I couldn't make it. I was delayed by the traffic. 

You have to keep on learning if you want to keep ______ with the development of modern science and technology.

Although it doesn't look like＿，the entire cathedral is made of wood.

I couldn’t stand the          of not being able to help when my best friend was in trouble.

The monitor wanted to buy two_______ stamps, but the salesgirl only sold him_______ these stamps.