问题
选择题
What _____ over there?[ ]
A. is happening
B. is happened
C. happen
D. happens
答案
答案：A
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What _____ over there?[ ]
A. is happening
B. is happened
C. happen
D. happens
答案：A
下表中对应关系正确的是
| A | CH3CH3+Cl2 CH3CH2Cl+HClCH2=CH2+HCl | 均为取代反应 |
| B | 由油脂得到甘油 由淀粉得到葡萄糖 | 均发生了水解反应 |
| C | Cl2+2Br‾=2Cl‾+Br2 Zn+Cu2+=Zn2++Cu | 均为单质被还原的置换反应 |
| D | 2Na2O2+2H2O+4NaOH+O2↑ Cl2+H2O="HCl+HClO" | 均为水作还原剂的氧化还原反应 |
CH3CH2Cl