—Will you give me a hand? I have some trouble_______ the scientific problem.—Don't worry. I'll try my best to help you _______.
_________Tom is not at home. He __________in the library.
Mr. Black is ___________to carry __________.
This man has _________ friends because he is not friendly.
Who taught them to ride bicycles? __________ They taught __________.
Are you reading a newspaper? Did you find __________ in it?