题1：He has been studying here for three years, by next sunmer he ( B ).

A. wrill graduate

B. will have graduated

C. will be graduated

D. will be graduating

题2：he's been studying here for three years and by next July he (  D ).
A. will have graduated 

B. will be graduated

C. will be graduating 

D. will graduate

请问：题2的A选项为什么不可以呢？难道是并列句的两个简单句时态独立互不受影响？但就算拆开了看，by+将来时间，题2用将来完成也是可以的吧？有点不理解，感谢老师们答疑解惑。