设备抽真空时，可以用抽真空的时间长短来估计真空度，抽真空所连接的管路一般不超过5米。
参考答案：错
根据所给信息写出启事牌。
Paul lost his dictionary. It is blue. It is new. His phone number is 735-2298. 在Lost中要写清楚所丢失
的事物及其颜色和新或旧，及失主的电话号码。
________________________________________________________________________________
___________________________________________________________________________________
I fell in 1ove____the beautiful city of Shanghai while I was on vacation there.
A．with
B．on
C．to
D．in
