A:shouldn't
B:wouldn't
C:mustn't
D:needn't
某人在吃肉时,牙缝里卡了一点瘦肉丝,经过了两天仍然没有被消化,这是因为( )
用平底锅烙饼,每次最多只能烙2张饼,两面都要烙,每面3分钟.烙4张饼最快用( )完成.