Passage Two
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.

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