生物学家借助新的显微技术，成功观察到小于200纳米的粒子。下列分散系中，分散质粒子半径最小的是( )
| A．雾 | B．Fe(OH)3胶体 | C．石灰乳 | D．KNO3溶液 |
His sister left home in 1998, and _______since. 
| A．had not been heard of | B．has not been heard of |
C．had not heard of | D．has not heard of |
What do you mean, there are only ten tickets? There _____ be twelve
| A．should | B．would |
C．will | D．shall |
Could I speak to ______ is in charge of International Sales please?
| A．who | B．what |
| C．whoever | D．whatever |
How much _______ she looked without her glasses!
| A．well | B．good | C．best | D．better |
Let’s go to ______ cinema – that’ll take your mind off the problem for _____while.
| A．the; the | B．the; a | C．a; the | D．a; a |