My father is good at ____ tennis? [ ]
A. to play
B. play
C. playing
D. to playing
答案:C
GP100-C3A型高频感应加热设备电压负反馈过强可造成整流输出电压()
A.过高
B.过低
C.不稳
D.无输出
关于肠结核的描述,正确的是()
A.平片常有"狗耳征"
B.肠结核好发于回盲部
C.通常分溃疡型、平坦型和增生型
D.病变肠段明显增宽、延长
E.原发灶以腹腔结核最常见