He said that not until the heavy snow blocked the express _________ how serious the weather was.
| A．did the tourists realize | B．the tourists realized |
| C．the tourists did realize | D．didn’t the tourists realize |
I am too tired. I _____ my homework all morning.
A have been doing B did C do D have done
_____ we know, Mr. Black is an expert on language teaching.
A As B That C Which D What
–You are twenty minutes late.
--Sorry, my car _____ on my way here.
A broke up B broke off
C broke away D broke down
This milk doesn’t taste _____ this morning.
A well B nicelyC good D lovely
The letter is from my sister, _____ is working in Beijing.
A which B that C whom D who