add-on
附赠品，附加优惠 

例句：
The cost of the holiday tour to Hawaii included six nights' stay at a hotel, but as an add-on, every extra night was available at a discount.
去夏威夷度假旅行的费用中包括六个晚上的旅馆住宿费，不过作为附加优惠，每多住一晚，其费用可以打折。
 

put...into effect
生效
    
例句：
The contract will be put into effect on March 3, 2000.
该合同将于2000年3月3日生效。
 

I've got my hands full.
我手头正忙。    

对话：
A: Jack, would you like to go out for a walk with me?
B: I'd love to, but I've got my hands full now. I'm preparing for tomorrow's exam.
　
A：杰克，你愿意和我一起去散步吗？
B：我很想去，可我现在正忙着。我在准备明天的考试。