当NPN三极管发射结电压小于0V;集电结电压小于0V时,三极管的工作状态是状态。
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listen to the conversation again and complete the conversation.Engineer 1: The 1______ for the new office building looks a little high.Engineer 2: Yeah, but our budget might not 2_____ ______Engineer 1: Maybe we can make it cheaper. Let's look at some alternative 3______Engineer 2: Okay. What materials are you thinking about changing?Engineer 1: Well, the estimate included 4 _____ ______Engineer 2: What's wrong with that? Porcelain tiles 5_____ ______Engineer 1: But they're also really expensive. We could save money by getting 6_______ ________ instead.Engineer 2: That's a good idea.
Listen to a conversation between two engineers. Choose the correct answers.
A. how expensive ceramic tiles are
B. why the budget is so low
C. which materials are affordable
D. where to buy cheaper materials
在T-SQL语言的命令格式中,( )表示内容是必选的。
A. < >
B. { }
C. [,…n]
D. [ ]