蟾蜍发育过程中，能用肺呼吸的是[ ]
A．受精卵
B．蝌蚪
C．成体
D．蝌蚪和成体
答案：C
在各种非创伤性脑出血中占首位的是（）
A.动脉瘤
B.脑动静脉畸形（AVM）
C.高血压脑出血
D.血友病
E.肿瘤卒中
Because the shop _____, all the T-shirts are sold at half price.[ ]
A. has closed down
B. closed down
C. is closing down
D. had closed down
