Many people say they love birds but some plant trees some make cages.A. untilB. thoughC.

问题补充：

Many people say they love birds, but some plant trees some make cages.

A. until

B. though

C. unless

D. while

答案：

A. until

B. though

C. unless

(答案→)D. while

解析：考查连词：A. until直到，B. though虽然，C. unless除非，D. while然而，句意是：很多人说喜欢鸟，但一些人种树，一些人做鸟笼。选D。