日本血吸虫病早期的病理变化主要由下列哪种因素引起（）
A.虫卵
B.子胞虫
C.田胞蚴
D.毛蚴
E.尾虫蚴
参考答案：A
Cathy is taking notes of the grammatical rules in class at Sunshine school, where she ____English for a year.
A．studies
B．studied
C．is studying
D．has been studying
简述正确对待早恋的方法。
