An authorization from the head of human resources department is needed for _____  to each employee's  personnel files.
A) accessing  B) access  C) accessory D) accessed 
The hotel has rooms available for anyone who plan on ____  in  Detroit during the annual conference.
 A) stay  B) to stay C) staying  D)stayed
第一题选B,第二题选C,第一题答案上的解释是“空格前面是for,所以要填入名词”,我没有理解.还有第二题是不是就是plan on doing sth.