下列说法中不正确的是( )。 A.离子化合物中不一定含有金属元素 B.由不同原子

题型:选择题

问题:

下列说法中不正确的是(  )。

A.离子化合物中不一定含有金属元素

B.由不同原子所形成的纯净物一定是化合物

C.在含有阳离子的化合物中,一定含有阴离子

D.含有金属元素的离子不一定是阳离子

考点:化学键与化学反应中能量变化的关系
题型:选择题

制动阀调整不当是气压制动系统制动不良的原因之一。()

题型:选择题

现浇水磨石地面磨石磨光后用()进行补浆。

A、湿布条蘸水泥浆

B、刷子蘸浆

C、干水泥

D、抹子

题型:选择题

I was a single parent of four small children, working at a low paid job. Money was always tight, but we had a (1) over our heads, food on the table, clothes on our backs, and if not a lot, always (2) . Not knowing we were poor, my kids just thought I was (3) . I’ve always been glad about that.

It was Christmas time, and although there wasn’t (4) for a lot of gifts, we planned to celebrate with a family party. But the big (5) for the kids was the fun of Christmas (6) .

They planned weeks ahead of time, asking (7) what they wanted for Christmas. Fortunately, I had saved MYM120 for (8) to share by all five of us.

The big (9) arrived. I gave each kid a twenty-dollar bill and (10) them to look for gifts of about four dollars each. Then everyone scattered. We had two hours to shop; then we would (11) back at the "Santa’s Workshop".

Driving home, everyone was in high Christmas spirits, (12) my younger daughter, Ginger, who was unusually (13) . She had only one small, flat bag with a few candies—fiftycent candies! I was so angry, but I didn’t say anything (14) we got home. I called her into my bedroom and closed the door, (15) to be angry again. This is what she told me.

"I was looking (16) thinking of what to buy, and I (17) to read the little cards on the ’Giving Trees’. One was for a little girl, four years old, and all she (18) for Christmas was a doll. So I took the card off the tree and (19) the doll for her. We have so much and she doesn’t have anything. "

I never felt so (20) as I did that day.

2()

A.little 

B.less 

C.enough 

D.more

题型:选择题

在优先级相同的情况下,多路访问网络上PIM-DM路由器的DR选择是根据()

A.选择RouterID大的为DR

B.选择RouterID小的为DR

C.选择IP地址大的为DR

D.选择IP地址小的为DR

题型:选择题

发生该事故的主要原因是驾驶人倒车前没有进行安全确认。

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