We laugh at jokes, but seldom _____ about how they work.
| A．we think | B．think we |
| C．we do think | D．do we think |
The soldiers soon reached ________ was once an old temple ________ the villagers used as a school.
| A．which, where | B．where, which | C．what, which | D．what, where |
After Chang’e-3 landed on the moon on Dec 14, China became the third country _________ this after the US and the former Soviet Union.
| A．having achieved | B．achieving | C．achieved | D．to have achieved |
---Excuse me, has the train from Beijing arrived yet?
--- ________, you are three quarters earlier. It's only 9 now.
| A．Unconsciously | B．Instantly | C．Absolutely | D．Actually |
The speed limit for bicycles on campus is 15 mph, ___________ otherwise posted.
| A．unless | B．until | C．since | D．however |
In manufacturing, cheaper materials are constantly being for the better, more expensive kind.
| A．maintained | B．cancelled | C．substituted | D．deposited |