噬菌体、蓝藻和酵母菌都具有的物质或结构是[ ] A．细胞壁 B．细胞膜 C．核酸

熔化极混合气体保护焊尤其适用于（）等黑色金属材料的焊接。

A、碳钢

B、合金钢

C、不锈钢

D、铸铁

调节器的正、反作用方向是什么？

小强和外婆在月下乘凉，小强说：“外婆，您和妈妈的年龄差恰好是我年龄的3倍。”外婆笑着说：“你们母子俩的年龄加起来还比我少18岁呢!”问：小强的年龄是多少岁( )

A．8

B．9

C．10

D．11

下列程序的功能是：将数据1，2，…，10写入顺序文件Base．txt中，请填空。　　Private Sub Form_Click()　　　Dim i As Integer　　　Open【】　As #1　　　For i=1 To 10　　　　　【】　　　　Next i　　　Close #1 　　End Sub

Sometimes we have specific problems with our mother; sometimes, life with her can just be hard work. If there are difficulties in your (1) , it’s best to deal with them, (2) remember that any (3) should be done (4) person or by letter. The telephone is not a good (5) because it is too easy (6) either side to (7) the conversation.

Explain to her (8) you find difficult in your relationship and then (9) some new arrangements that you think would establish a (10) balance between you. Sometimes we hold (11) from establishing such boundaries because we are afraid that doing (12) implies we are (13) her. We need to remember that being (14) from our mother does not (15) mean that we no longer love her. If the conflict is (16) and you cannot find a way to (17) it, you might decide to give up your relationship with your mother for a while. Some of my patients had (18) "trial separations". The (19) allowed things to simmer down, enabling (20) .

（12）（）

A.it

B.which

C.what

D.so