The author implies that ______.
A. participation in interesting activities relating to a subject improves one's achievement in that area
B. too many children are lazy and have poor study habits
C. school principals should do more than their share in interpreting the curriculum to the parents
D. teachers should occasionally make home visits to parents
吊装工程量较大的普通单层装配式结构，宜选用( )。
A. 塔式起重机
B. 履带式起重机
C. 轮胎式起重机
D. 汽车式起重机
低压的汞蒸气弧光放电灯是指( )。
A. 卤钨灯
B. 日光灯
C. 水银灯
D. 高压水银灯
细胞分裂增生时，DNA的合成过程称为（ ）
A. 复制
B. 逆转录
C. 转录
D. 转录后加工
E. 翻译
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