相同比例的青蓝颜料和黄色颜料混合得到的颜色应是（）
A.黄色
B.绿色
C.大红色
D.蓝色
参考答案：B
We have finished the project finally . No one can imagine the difficulty we had _____the problem,
A．to solve
B．solved
C．solving
D．solve
锈病主要为害哪些科的苗木？
