【单选题】The purpose of open space institute purchasing scenic and natural land is to____
A.
Do research in open area
B.
Upgrade the scenic spots to state level
C.
Promote tourism and real estate
D.
Preserve it from being developed
【单选题】William Scott would most probably agree that caffeine helped_______________.
A.
reduce the risk of Alzheimer's disease
B.
retard the process of cognitive decline
C.
balance the production of female hormones
D.
protect both men and women from diseases
【判断题】津液是构成人体和维持人体生命活动一切的正常水液的总称。 如胃液、肠液、泪液、唾液、汗液、尿液等。
【多选题】属于塑料的缺点是()
A.
耐热性差,一般只能在100℃以下使用,少数能在200℃左右使用
B.
塑料的热膨胀系数要比金属大3~10倍,容易受温度变化而影响尺寸的稳定性
C.
塑料在载荷作用下会缓慢地产生粘性流动或变形,即产生蠕变现象
D.
塑料在大气、阳光、长期压力或某些物质作用下会发生老化现象
【单选题】On open lifeboats,the purpose of the wire stretched between the davit heads is to().
A.
keep the movement of the davits at the same speed
B.
keep the davits from slipping when they are in the stowed position
C.
prevent vibration during lowering of the boat
【单选题】分子对接最初思想起源于FisherE.的