If you swim in a river or lake, be sure to investigate is below the water surface. Often there are rocks or branched hidden in the water.
| A．what | B．who | C．that | D．whoever |
I made a promise to myself ________ this year，my first year in high school，would be different.(2012·浙江)
| A．whether | B．what | C．that | D．how |
At first he hated the new job but decided to give himself a few months to see ________ it got any better.
| A．when | B．how | C．why | D．if |
It is still under discussion ________ the old bus station should be replaced with a modern hotel or not.
| A．whether | B．when | C．which | D．where |
The limits of a person's intelligence，generally speaking，are fixed at birth，but ________ he reaches these limits will depend on his environment.(2011·安徽)
| A．where | B．whether | C．that | D．why |
We've offered her the job，but I don't know ________ she'll accept it.(2011·山东)
| A．where | B．what | C．whether | D．which |