I’m surprised at ______ the house empty.
A. find
B. finding
C. found
D. having found
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Ifyouinsiston______something, doitevery day.
A. do
B. doing
C. to do
D. have done
Suppose you aremaking a phone call. Match “what you want to do” with “what you would say”.
测定植物试样中磷含量的一种试验方案是:称取一定质量的含磷试样,处理后将磷沉淀为MgNH4PO4,经过滤、洗涤、再溶解,用EDTA标准溶液滴定溶解后的Mg2+,可选用的指示剂是()
A. 甲基橙
B. 淀粉
C. 铬黑T
D. 钙指示剂
有两种化合物A和B具有同一化学式:Co(NH3)3(H2O)2ClBr2。在干燥器中,1mol A很快失去1mol H2O,但在同样条件下,B不失去H2O。当AgNO3加入A中时,1mol A沉淀出1mol AgBr,1mol B沉淀出2mol AgBr。则A和B的化学式分别为________和 __________。