带有一个单位正电荷的粒子是（）
A.中子
B.α粒子
C.β-粒子
D.γ光子
E.质子
参考答案：E
解析：此处只有质子带一个单位的正电荷。
— Did you ask Sophia for help?
— I ___ need to . I managed perfectly well on my own.[ ]
A. wouldn't
B. don't
C. didn't
D. won't
灌浆期要求适宜的田间持水量为（）。
