用竖式计算.
42×19
354÷6
64×35
690÷3
56×23.
42×19=798;
354÷6=59;
64×35=2240;
690÷3=230;
56×23=1288;
Plastic bags are provided for our convenience but they have also ___ the pollution of the environment.[ ]
A. adapted to
B. turned to
C. contributed to
D. looked forward to
假设期权标的股票前收盘价为10元,合约单位为5000,行权价为11元的认购期权的前结算价为1.3元,则每张期权合约的初始保证金最近接近于()元。
A、10000
B、14000
C、18000
D、22000