The manager came over and asked the customer how ___________.
| A．did the quarrel come about | B．does the quarrel come about |
| C．the quarrel has come about | D．the quarrel had come about |
It is not until recently ______ the scientists have found proof of there being water on Mars.
| A．when | B．that | C．how | D．what |
______ our horizons of thinking, but it also saves us time and energy.
| A．Not only does the Internet expand | B．Not only expands the Internet |
| C．Not only the Internet expands | D．Not only the Internet does expand |
An excellent way to help memory is to connect information with pictures, which ______ as a memory-link method.
| A．considers | B．is considering | C．is considered | D．Considered |
Air bags for cars were invented _____ lives. Without them more people would be injured in car accidents.
| A．saving | B．saved | C．to save | D．to have saved |
Last year John earned _______ his brother did, who has a better position in a bigger company.
| A．twice as many as | B．twice as much as |
| C．twice as more as | D．twice much as |