The Internet is a wonderful discovery,________of great significance to people’s lives.

were electric slippers invented? —Sorry. I don’t know. [ ]

Where were you at eleven o’clock this morning? —I ________ beef with my father at home at that time.

Do you know the man ______ is talking with your father?—Yes, he’s our head teacher.[ ]

There was __________rain last night and it’s _________cold now.