中考模拟，题型全面，实战演练。

I. 单项选择（共20小题，每小题1分，计20分）

选出可以填入空白处的最佳选项。

1. They had ___________ long vacation and paid __________ visit to Kunming.

A. the, a           B. a, the             C. a, a             D. the, the

2. Don’t trouble them now. They are busy ___________ their work.

   A. with            B. for               C. to              D. about

3. Look at these __________ wings. They are so beautiful.

   A. butterfly’s       B. butterflies          C. butterflies’s      D. butterflies’

4. The scientists have solved all those problems ____________ in the end.

   A. success          B. successful         C. successfully      D. succeeded