1. _______ that the demand for power continues to rise at the current rate, it will not be long before traditional sources become inadequate.
A. Concerning
B. Ascertaining
C. Assuning
D. Regarding

2. Over the past ten years, natural gas production has remianed steady, but _______ has risen steadily.
A. consumption
B. dissipation
C. disposal
D. expenditure

3. Doctors are often caught in a _______ because they have to decide whether they should tell their patients the truth or not.
A. puzzle
B. perplexity
C. dilemma
D. bewilderment

4. The two most important _______ in making a cake are flour and sugar.
A. elements
B. components
C. ingredinents
D. constituents

5. The old lady has developed a _______ cough which cannot be cured completely in a short time.
A. perpetual
B. permanent
C. chronic
D. sustained


答案请查看：点击此处>>>