同学们做了180朵纸花，每25朵扎成一束，已经扎了6束，还剩多少朵花？
180-25×6
=180-150
=30（朵）
答：还剩30朵花．
原发性腹膜炎和继发性腹膜炎的主要区别在于（）
A.腹痛性质
B.疾病严重程度
C.腹肌紧张程度
D.病原菌的种类
E.腹腔是否有原发病灶
27. He often thinks of ______ he can do more for his country, so he is highly spoken of by the people throughout the country.
A．what
B．that
C．how
D．Whatever
