大学英语六级15

大学英语四六级考试；四六级英语；四六级英语报名时间；四六级成绩查询；四六级查分；英语四六级听力‘英语四六级真题；英语四六级2019；四六级英语考试；大学英语；四六级英语真题听力；四六级英语听力录音；

大学英语六级15.mp300:0002:55

29.

A. To Michigan.

B. To China.

C. To Maryland.

D. To Canada.

30.

A. To clear up the eggs of insects.

B. To help trees deliver water.

C. To look for the signs of insects.

D. To prepare for cutting down trees.

31.

A. Collect ash tree seeds for experiment.

B. Preserve the healthy ash tree seeds.

C. Set up a new seed bank for research.

D. Develop a new breed of ash tree.