变压器可以变换：（） A.交流电压 B.直流电压 C.功率 D.频率

如果对于函数f（x）定义域内任意的x，都有f（x）≥M（M为常数），称M为f（x）的下界，下界M中的最大值叫做f（x）的下确界．定义在[1，e]上的函数f（x）=2x﹣1+lnx的下确界M=（    ）

句型转换

1. There won't be any elephants if we don't help them.

    There will __________ __________ elephants if we don't protect them.

2. There was a heavy rain last night.

    It __________ __________ last night.

3. The plane will leave Shanghai at 10:35 this evening.

    The plane __________ Shanghai at 10:35 __________.

4. The Chinese government wants to help these birds in danger.

    The Chinese government wants to help these __________ __________.

5. Every year, a lot of tourists go to Zhalong to watch birds.

    Every year, __________ tourists go __________ in Zhalong.

6. She sings beautifully.(划线提问)

    __________ __________ she sing?

7. He went to Hongkong for a short stay.( 划线提问)

    __________ __________ he go to Hongkong?

8. It is not right to hunt in a protected area. It is not right to fish there ,either.

    It is __________ to hunt __________ fish in a protected area.

9. Zhalong Nature Reserve is over 210,000 hectares in area .

    Zhalong Nature Reserve __________ __________ area of more than 210,000 hectares.

10. I like the seagull best.( 划线提问 )

    __________ __________ do you like best?

(1).不宜在感冒期间服用滋补性中药（）
(2).风热感冒适用（）
(3).风寒感冒适用（）
(4).解表散热，疏肝和胃（）

A．感冒清热颗粒 

B．抗病毒口服液 

C．两者均是 

D．两者均不是

某二叉树中度为2的结点有18个，则该二叉树中有 (2) 个叶子结点。