If nothing________，the oceans will turn into fish deserts.
| A．does | B．had been done |
| C．will do | D．is done |
____ hands and knees Helen Thayer got the tent up.
| A．In | B．At | C．With | D．On |
The woman looks so worried. She seems ____ something valuable.
| A．lose | B．losing | C．to have lost | D．having lost |
For women life sometimes seems ____ it is for men.
| A．twice as hard as | B．as twice hard as | C．as hard twice as | D．as hard as twice |
____ his homework, the boy went out to play games with his friends.
| A．Finished | B．Having finished | C．Being finished | D．To finish |
Guilin is famous ____ its beautiful hills and rivers, while Kunming is famous ____ the Spring City.
| A．for; for | B．as; as | C．as; for | D．for; as |