As we all know， tigers are in danger of dying out.
| A．the；不填 | B．不填；不填 | C．the；the | D．不填；the |
---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 |