Hard work and lack of sleep have ________her beauty and youth in recent years. A. worn out B.tried out C made out D.sent out 答案:A 解析: worn out耗尽,筋疲力尽; tried out试验, 考验, 提炼;make out书写, 填写, 拼凑, 进展, 说明, 设法应付, 理解, 辨认出; sent out发出。为除去下列物质中混有的少量杂质,所用试剂正确的是( )
选项
物质
杂质
所用试剂
A
CaO
CaCO3
稀盐酸
B
CO
O2
灼热Cu
C
FeCl2溶液
CuCl2
铁粉
D
CO2
HCl
NaOH
A、AB、BC、CD、D