第二部分选择题 (共70分)
I.语言知识及应用（共两节，满分30分）
第一节单项选择（共15小题；每小题1分，满分15分）
根据句子的语法结构，从A，B，C和D项中，选出最佳选项，并在答题卡上将该选项涂黑。
1. The research is so designed that, once _______, nothing can be done to change it.
A. begins B. having begun C. begun D. beginning
2. The bell _______ the end of the period rang, _______ our heated discussion.
A. indicated; interrupting B. indicating; interrupting
C. indicating; interrupted D. indicated; interrupted
3. _______ to sunlight for too much time will do harm to one’s skin.
A. Being exposed B. Exposed
C. Having exposed D. After being exposed
4. _______ in the queue for half an hour, Tom suddenly realized that he had left his wallet at home.
A. To wait B. Having waited C. Have waited D. To have waited
5. Jack went to college last year, _______ to return home until he achieves his goal.
A. determined not B. determining not
C. not determined D. not determining
