用括号内所给动词的正确形式填空。

1. —I phoned you yesterday morning, but you were not in. 

   —We _______(fish) by the river.

2. _______(make) sure that there are no mistakes, he will check the paper carefully.

3. Is the washing machine I have used for a long time worth _______(fix)?

4. There _______(not be) much snow here in the past three years.

5. I don't know if we _______(show) around the History Museum tomorrow afternoon.

现代麻醉机的基本要求是()

A．气体流量准确

B．供氧充足，排除CO完全

C．无效腔小

D．呼吸阻力低

E．具有安全报警装置系统