They look similar _____ appearance, but quite different_____ other aspects.
| A．to; in | B．in; from | C．to ;from | D．in; in |
As we know, penicillin became the greatest drug of the 20th century, ______ millions of lives.
| A．to save | B．saving | C．saved | D．Save |
—How long _______ in Shanghai?
—I will be there attending a conference and giving a speech, which will take about 3 days.
| A．have you stayed | B．are you staying | C．do you stay | D．did you stay |
If he _______ the opportunity at that time, he would be the new department manager now.
| A．seized | B．should seize | C．has seized | D．had seized |
To everyone’s amazement now, technology ________ faster than most people can keep pace with.
| A．is changing | B．will change | C．changes | D．has changed |
It was not until the early 1950s ______most tape recorders began using plastic tape as they do today.
| A．when | B．which | C．that | D．Before |