(判断题)27: 汇点式外部接线方式各个I/O电路有一个公共点，共用一个电源。（ ） A: 错误 B: 正确 ...

(单选题)2: Either the dean or the principal ______ the meeting. A: attends B: attend C: are attending D: have attended ...

(单选题)15: _________ she couldn’t understand was __________ fewer and fewer students showed interest in her lessons. A: What; why B: That; what C: What; because D: Why; that ...

(单选题)22: I don’t know why he is late.　　Nor do I. He _____ an accident. A: could have had B: should have had C: might have had D: must have had ...

(单选题)4: Smoking, _______ is a bad habit, is, however, popular. A: that B: which C: it D: though ...

(单选题)17: Last summer we visited the West Lake, ______Hangzhou is famous in the world. A: for which B: for that C: in which D: what ...

(单选题)18: The public ______ generous in their contributions to the earthquake victims. A: is B: was C: are D: has been ...

(单选题)12: _________ we’ll go camping tomorrow depends on the weather. A: If B: Whether C: That D: Where ...

(单选题)20: _____ the rain stops, we' ll set off for the station. A: Before B: Unless C: As soon as D: Though ...

(单选题)2: It is pretty well understood _________ controls the flow of carbon dioxide in and out the atmosphere today. A: that B: when C: what D: how ...