Could you cover for me on Tuesday?
你星期二能帮我代班吗？

cover 覆盖；遮住
cover sth with sth
用...遮住...
cover his face with hands.
用手遮住脸
cover for sb
代替某人工作（因为某人生病或离开）；包庇某人
I covered for him when he was ill.
他生病的时候是我替他的班。
Why would she cover for someone who was trying to kill her?
她为什么要包庇那个试图杀死她的人呢？

A:Could you cover for me on Tuesday? I'm not coming back until Wednesday.
你星期二能帮我代班吗？我要到星期三才回来。
B:Sure.What's up?
当然可以。有什么事情吗？
A:We're going to the beach for the weekend.
我们周末要到海边去玩。
B:Are you going fishing?
你要去钓鱼吗？
A:No.Just some fun in the sun. We really need to get away and relax for a few days.
不，只是去晒晒太阳。我们真的需要去放松几天了。
B:Well,don't worry .I'll take care of the business for you. Have fun.
不要担心，我会替你做好工作的。你好好的玩吧。