该句中不用被动的原因是因为“when”引导的是时间状语从句。“when the door opens” 不用被动的原因是因为“when”引导的是时间状语从句，而且在这个从句中，主语“the door”和谓语动词“opens”之间是主动关系。这种表达方式是正确的，因为它符合英语语法规则。
suddenly it began to rain.(2)when用作并列连词,意为”就在此时(突然)”。He was still smiling when the door opened and hiswife came in。他仍在笑着,这时门突然开了,他的妻子走了进来。when作并列连词时,常用于下面的句型中:①be doing sth.when。。。正在做……,归突然……纳|be about to do ...
When Mark opened the door,he saw a women standing there.He___her before.( )A.never saw.B. had never seen.C. never sees.D. has never seen. 相关知识点: 试题来源: 解析 答案:B.根据句意可知,他从没看到过这个人.应该在他开门之前没有看到过这个人.开门是过去,没有看到过她应该用过去完成...
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open or shut, while others may use infrared beams which trigger an alarm when they detect that a door has been opened or that someone has walked through a doorway. Wireless door alarms may operate with batteries which need to be replaced, or they may be plugged in or wired to the wall....
1.General alarm mode It alarms when doors/windows are open; Stops when they are closed. 2.Constant Alarm Mode It alarms at least 30 seconds when triggered. 3.Time Delay Mode It sounds "di-di-di" when doors/windows opened 15 seconds later (Can set the delay time 3/15/30/60 seconds,...
A. opened B. close C. unlocking D. open 相关知识点: 试题来源: 解析 D 句意:我到家时发现门开着。考查形容词辨析题。find+宾语+形容词,表示宾语处于某种状态。A是动词open的过去式,B是动词close的原形,C是动词unlock的现在分词形式,都不是形容词,可排除。open开着的,敞开的,形容词;根据句意语境,...
When Mark opened the door, he saw a woman standing there. He ___ her before. A. never saw B. had never seen C. never sees D. has never seen 相关知识点: 试题来源: 解析 B 解析: 由过去时态构成的句子语言环境可以看出,应首先排除C、D两个选项。再由句子中的before可以看出是说在那...
The device has the advantages that the device can automatically give alarms when the rear doors are opened and stop all work, any maloperation caused by opening of the rear doors can be completely prevented in the production process, personal safety of operators are protected, normal use of the...
When it comes to ensuring the security of your home, a door alarm is a great place to start. Check out our guide to the best door alarms!