买入股票认购期权：收益无限，损失有限，最大损失为（）。
A.权利金
B.不确定
C.无限
D.签订期权合约时，期权合约标的股票的初始价格
参考答案：A
Switzerland is ______ a place to indulge in all your favorite winter sports; it's also a marvelous spot to relax.
A．rather than
B．more than
C．else than
D．other than
一般对致癌物制定的实际安全剂量在人群中引起的肿瘤超额发生率不超过
A．10-2
B．10-3
C．10-4
D．10-5
E．10-6
