题目

13．Many medical scientists are racing__________time to find a cure for H1N1 as soon as possible.        A．on     B．against      C．for    D．In 答案：B下列函数中，最小正周期为π2的奇函数是（　　）A．y=sin4xB．y=tanx2C．y=cosxD．y=sinxcosx