羟基蒽醌类成分可发生下列哪些化学反应()
A.活性亚甲基反应
B.无色亚甲基蓝反应
C.菲戈尔反应
D.Bomtrager’s反应
E.Legal反应
参考答案:C, D
执行下面的程序段,x的值为【】。 Private Sub Command1_Click() For i=1 To 9 a=a + i Next i x=Val(i) MsgBox x End Sub
---Tom is so worried about the test that he said he was going to study all night.
----Tell him he should quit _________and get some help.
A.to have worried
B.to worry
C.worring
D.from worrying