如图所示，理想变压器原线圈输入交流i=Imsinωt，副线圈按有一电流表和负载电

冰岛火山灰曾严重影响欧洲飞机的正常飞行．火山灰是细微的火山碎屑物，它质地坚硬、不溶于水，含有硫、钙、硅、氧及重金属等成分．这里所说的成分是指（　　）

A．元素

B．原子

C．分子

D．单质

根据要求完成句子。

1. We publish our school newspaper twice a month. (改为被动语态)

     Our school newspaper ______ ______ twice a month.

2. The meeting began half an hour ago. (同义句)

    The meeting has ______ ______ for half an hour.

3. I heard that she was singing at that time. (改为简单句)

    I heard ______ ______ at that time.

4. My brother gave my mother a present on her birthday. (改为被动语态)

    A present ______ ______ to my mother on her birthday.

5. My friend seems to be very angry. (同义句) 

   ______ seems that my friend ______ very angry.

この先は道が＿＿＿して危険なんです。

A．そろそろ

B．のろのろ

C．でこぼこ　　

D．とことこ

1927—1936年，南京国民政府统治的前十年，中国民族资本主义（ ）

A．由于列强的侵略而处于萧条状态

B．由于国民政府的措施而得到较快发展

C．由于官僚资本的挤压而萎缩

D．由于日本的经济侵略而陷入困境

紧急情况后，多少天内报告？