At times the balance in nature is ______，resulting in a number of possibly unforeseen effects.
| A．troubled | B．confused | C．disturbed | D．puzzled |
15．You may ________ the textbook if you don’t know the answer to the question.
| A．refer to | B．deal with | C．look up | D．look into |
14．Jim insisted that the book Mr. Black referred to ________.
| A．was worth to be bought | B．was worth buying |
| C．being worth buying | D．be worth buying |
13．Being a good listener is a kind of quality and that’s ________ it takes to keep friendship.
| A．how | B．what | C．which | D．Where |
12．I gave all the newspapers to them and spared ______, though I didn’t have _____ in my flat.
| A．nothing; much | B．none; much | C．nothing; many | D．none; many |
11．I’d rather you did some housework when you are free, but you ________
| A．weren’t | B．didn’t | C．wouldn’t | D．don’t |