I do every single bit of housework ______ my husband Bob just does the dishes now and then．
| A．since | B．while | C．when | D．as |
The Great Wall, _____ to be the longest wall in the world, runs across China like a huge dragon．
| A．saying | B．to say | C．said | D．being said |
It is widely believed among bioengineers _____ it will be possible to create life under laboratory conditions．
| A．which | B．what | C．that | D．when |
Teaching ___ child to cook will improve many of ___ skills that he or she will need later in life．
| A．/; the | B．a; the | C．a ; / | D．the; a |
—Rather than ___ on a crowded bus, he always prefers ___ a bicycle.
| A．ride; to ride | B．riding; ride | C．ride; ride | D．to ride; Riding |