Don't _____ people who are in trouble[ ]
A. laugh
B. smile
C. laugh at
答案：C
X线片上有节育器但宫腔探查无节育器，应考虑
A．节育器过大B．节育器过小C．节育器变形D．节育器入腹腔E．节育器低位
食用菌的生活史有哪些类型？
