Tom was about to close the window ___ his attention was caught by a bird.
| A．when | B．if | C．and | D．till |
---Your composition is full of mistakes.
---I wish I______more careful.
| A．would have been | B．had been | C．would be | D．were |
______life began on the earth is one of the biggest puzzles to scientists.
| A．How | B．What | C．Where | D．That |
---Let’s throw a surprise party for mom’s 50th birthday.
---That’s a good idea．We______several of her friends.
| A．invite | B．have invited | C．are inviting | D．will invite |
______fit, we ought to learn more about our body and be careful with what we eat.
| A．Keeping | B．To keep | C．Having kept. | D．To have kept |
Mike must be angry with me, for he walked______me without even saying hello.
| A．past | B．on | C．at | D．over |