---You are late again! We _________you could attend the assembly on time.
---Sorry, I __________to my office to get my papers.
| A．think, went | B．thought, have gone | C．think, were going | D．thought, went |
Everyone knows that _______ is dangerous to play with fire, but _______ is difficult is to prevent children from playing with fire.
| A．it, it | B．what, what | C．it, what | D．what, it |
Not until the early years of the 19th century ________ what heat was.
| A．man did know | B．did man knew |
| C．didn't man know | D．did man know |
Tom kept quiet about the accident ________ lose his job.
| A．so not as to | B．so as not to |
| C．so as to not | D．not so as to |
A driver should __ the road when .
| A．concentrate on; drive | B．concentrate in; driving |
| C．concentrate to; drove | D．concentrate on; driving |
_______ in a friendly way, their quarrel came to an end.
| A．Being settled | B．Settled |
| C．Settling | D．Having settled |