引起Pick痴呆的主要病变部位为
A.顶额叶B.顶颞叶C.额颞叶D.颞枕叶E.额枕叶
参考答案:C
--- Where is Jack?
--- He _________ football on the playground with those AFS students, but I am not sure.
A.must be playing
B.must have played
C.may be playing
D.may have played
什么是生态系统的分解作用影响分解作用的主要因素有哪些论述分解作用的生态学意义。