第6課

　　關于逗號的一些知識
　　原則：逗號沒有能力連接兩個單獨的句子。
　　如何區分短語與句子？一個結構如果有完整的謂語部分就是句子。
　　何為完整的謂語部分？如果能判斷出一個結構的時態就可以稱這個結構為完整的謂語部分。
　　在什么樣的情況下一個逗號可以將句子分成兩部分，而這兩部分都有完整的謂語呢？
　　1 兩個句子中間有連接詞連接；
　　2 這兩個句子是主從句關系（主從句之間一定要有句子引導詞來引導）。
　　10. Walter offered us a lift when he wasleaving the office, but our work _A_, we declined the offer. [declined v. 婉言謝絕]
　　A not being finished B not having finished
　　C had not been finished D was not finished
　　42. A survey was carrie3d out on the deathrate of new-born babies in that region, _D_ were surprising. [survey 調查]
　　A as results B which results C the results of it D the results of which
　　51. All flights _D_ because of thesnowstorm, many passengers could no nothing but take the train. [having beencanceled這里是獨立主格作原因狀語]
　　A had been canceled B have been canceled
　　C were canceled D having been canceled