1.bound to 绑定到；必定

例句:They are bound to take time to readjust after a holiday.
他们肯定需要时间重新适应假期结束后的生活。

2.bail out 保释

例句:He desperately needed cash to bail out the ailing restaurant.
他急需现金使经营惨淡的餐馆走出困境。

3.begin to 开始

例句:You can't begin to imagine how much that saddens me.
你都无从想象这让我有多悲伤。

4.refer to 参考；涉及

例句:The new law does not refer to land used for farming.
那条新法律并不涉及耕种用地。