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【单选题】
ChP古检测碑法中,加入醋酸铅棉花的目的是( )A.
除去硫化氢的影响
B.
防止瓶内飞沫溅出
C.
使深化前进气体上身的速度温度
D.
使溴化汞试纸呈色均匀
E.
将五价砷还原成砷化氢
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皮皮学刷刷变学霸
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【简答题】(选做题)阅读图文材料,完成下列要求。 (24 分 ) 肉桂是生态经济树种,生长不耐积水、喜疏松肥沃且富含有机质的酸性沙壤,当空气湿度大于80%,温度为26~30°C时生长旺盛,较充足的阳光有利于树皮的增厚。一般在栽种5~6年后可砍树剥皮。树龄越长,皮越厚,质越好。肉桂全身是宝,其叶经蒸馏可得桂油,桂油是初级香料原料,国际市场普遍使用桂油深加工生产苯甲醛;树皮称桂皮,也是重要的天然香料、饮料配料和...
【单选题】Cars, buses and bikes ______ stop when the traffic light is red. [ ]
A.
must
B.
can
C.
may
D.
need
【单选题】You ________ stop when the traffic light turns red. [ ]
A.
can
B.
had better
C.
need
D.
must
【单选题】All the cars _____ stop when the traffic light is red. [ ]
A.
can
B.
need
C.
may
D.
should
【单选题】If the traffic light is red. You can't walk _____ the road. [ ]
A.
across
B.
through
C.
to
D.
along
【单选题】You _________ drive on when the traffic light is red.
A.
can’t
B.
needn’t
C.
mustn’t
D.
may not
【单选题】You ________ drive forward when the traffic light is red. [ ]
A.
shouldn't
B.
can't
C.
mustn't
D.
may not
【单选题】According to the types of signs, traffic light can be regarded as
A.
icon
B.
index
C.
symbol
D.
over sign
相关题目：
【单选题】You _________ drive on when the traffic light is red.
A.
can’t
B.
needn’t
C.
mustn’t
D.
may not