As there is less and less coal and oil, scientists are exploring new ways of making use of ______________ energy, such as sunlight, wind and water for power and fuel.
| A．abrupt | B．alternative | C．authentic | D．abstract |
After her time in hospital, Jenny's parents are afraid she has _____ in her lessons.
| A．fallen behind | B．fallen down | C．fallen back | D．fallen off |
—Look, John‘s fallen asleep at work!
—Oh, he must have ________ late last night.
| A．waken up | B．put up | C．taken up | D．stayed up |
—Won't you go shopping with your mother?
—No.________ she promises to buy me a new sweater.
| A．Now that | B．If only | C．As though | D．Unless |
The result is very important.It is supposed ______ a secret between you and me.
| A．to be kept | B．to keep | C．being kept | D．keeping |
Knowledge and learning are important if we want to be successful, but they may also ________our thinking.
| A．direct | B．limit | C．change | D．improve |