对放射最敏感的肿瘤是（）。
A.细胞分裂慢的肿瘤
B.高分化肿瘤
C.低分化或未分化肿瘤
D.囊腺癌
E.腺癌
参考答案：C
I turned down his invitation to dinner as I didn't want to ______ on him.
A．invade
B．disturb
C．interfere
D．impose
家庭是由（）的（）所构成的生活单位。
