1. Ozone is (an) unstable, (faintly) bluish gas (that) is the most (chemical) active form of oxygen. 答案是 C 不明白呀
2. The applications of electronic controls made____ by the microprocessor and computer storage have multiplied the uses of the modern typewriter.
A .it possible B. possible C. it is possible D. possibility
答案是B A 为什么不对呀?
3. Indigo is a vat color, ____ called because it does not dissolve in water.
A which it b it is c but d so
答案是D 真是难明白 我觉得C 是对的?
4. Most of ___ archaeologists know about prehistoric cultures is based on studies of material remains.
A these b what c which d their
答案是B 我选择的是C