搜题请搜索小程序“爱下问搜题”
问题
判断题
压力表安装连接处应加装密封垫片。
答案
参考答案：对
补全对话，情景问答
根据所给问句选正确答语。
( ) 1. What is Danny doing?
( ) 2. What season is this?
( ) 3. What is Jenny doing?
( ) 4. What are you learning?
A. It's summer.
B. She's taking off her dress.
C. He's skiing on the snow.
D. I am learning English.
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多项选择题
不停电电源系统由（）组成。
A、交-直流整流器
B、直-交流逆变器
C、UPS电源
D、配套的直流蓄电池组
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