I . 根据首字母或中文提示补全单词：(每题2分，共20分)
1. A He finished the report under the g_____________ of the professor.
2. B Don’t bother me when I am __________ off my feet.
3. A We were all weak from h___________ not having had food for over fourteen hours.
4. B Drivers must not exceed (超过) a m___________ of 55 miles an hour.
5. A He made the story so v_________ that we all believed it.
6. B Children lose their _____________ (天真) as they grow older.
