Don't ______ rules next time! [ ]
A. keep
B. kept
C. break
D. breaking
答案:C
原发性肝癌病人肝区疼痛特点是()
A.间歇性剧痛
B.持续性胀痛
C.阵发性绞痛
D.刀割样疼痛
E.烧灼样疼痛
用平面去截一个几何体,如果截面是梯形,那么所截的这个几何体有可能是______.