The big lake was contaminated with waste waters from nearby factories.
A. widened
B. blackened
C. polluted
D. mixed
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The parents have to restrain their daughter from playing cyber games.
A. disallow
B. reduce
C. prevent
D. confine
The manager talked over the requirement of the new job with him.
A. discussed
B. mentioned
C. accepted
D. rejected
某塑料管无毒、价廉,但抗冲击强度较差。经改性后具有较好的抗冲击性能和具有耐温度变化性能、抗蠕变性能,采用熔接方式连接,此管材为____。
A. 硬聚氯乙烯管
B. 聚乙烯管
C. 聚丙烯管
D. 聚丁烯管
47 制造容易且承压能力较好的容器是____。
A. 矩形容器
B. 圆筒形容器
C. 球形容器
D. 其他