【单选题】人类血清中含量最高、半衰期最长的Ig类别是。
【判断题】化学物品可能含有符合所有类别的危险品,尤其是易燃液体、易燃固体、氧化剂、有机过氧化物、无机过氧化物、毒性或腐蚀性物质。
【单选题】According to the passage, most ocean water evaporation occurs especially
A.
around the higher latitudes
C.
because of large-scale winds
D.
because of strong ocean currents
【多选题】氧化剂和有机过氧化物的主要危险有氧化性以及()。
【单选题】According to the passage, primitive ocean life begins to evolve into complex organisms ______.
A.
in the middle of December
B.
when Earth is cratered
C.
at the beginning of November
D.
when the land is still a lifeless waste