桃小食心虫和梨小食心虫幼虫最明显的区别在：（）
A.体色不同
B.体长
C.桃小无臀栉而梨小有4-7个臀栉
D.其它特征
参考答案：C
The World Health Organization gave a warning to the public without any ________ when the virus
of H1N1 hit Mexico in April, 2009.[ ]
A. delay
B. effort
C. schedule
D. consideration
类风湿结节是本病较特异的皮肤表现
