冰冻解冻去甘油红细胞血小板残余量（）。
A.≤1%
B.≤2%
C.≤2.5%
D.≤3%
E.≤4%
参考答案：A
Where's Tom? His mother ______ him now.
A．is looking for
B．will look for
C．has looked for
D．looks for
避孕方法中失败率最高的是
A．安全期避孕B．使用 * * 隔膜C．放置宫内节育器D．使用阴茎套E．按时口服短效避孕药
