Though great efforts have been on their study , Annie still can’t make any improvements , which makes her parents greatly ______ .

Do you know a spaceship flies at about nineteen kilometers ________ second?

______ the ancient Egyptians built the pyramids puzzled people for centuries.

You should have a part-time job during the summer holidays. — I don’t you, Mum. I am too young to do that.

What do you think of the young lady?— She is hard-working. She ________ all her effort into her work before she got ill.