１.Ｈere came___word that Obama was elected____president of USA.
A.a;the B.不填；不填 C.the;不填

2.It is playing computer games___he spends so much time that he fails all the exam.
A.which B.what C.in which D.that

3._______abstract,Galileo's theory was quite difficult to understand of his time。
A.sounding B.sounded C.To sound D.Having been sounded

4.While staying in Scotland alone,_____.
A.loneliness was always around me.
B.many interesting places were visited
C.I was a bit homesick
D.my friends in China encouraged me a lot

正确答案是B.D.D.C,为什么第一题不选A呢，还有第二题选C为什么不对呢，特别是第三题那四个选项分别是要用在什么情况下的啊，我就觉得sounding也对啊，第四题就完全模糊不知道怎么做出来的，请老师详细指教哈，谢谢了

最怕这样的题目了！
第一题：President of USA是头衔，不能用定冠词！
第二题是it is ...that...强调句型!
第三题我也有点疑惑：应该是强调时间的持续吧，感觉A也确实可用！
第四题强调staying的逻辑主语应该是I，所以不能用别的！
第五题是虚拟语气it is time that...后面接动词一般过去时！