be busy(doing)忙着(做某事)
be busy about忙于……
be careful t0(do)务必注意(做)
be certain to(do)一定(做)，必然(做)
be confident in对…有信心
be clever at擅长于
be composed of由…组成
be connected with与…有关
be covered with被…覆盖
be curious t0(do)很想(做)
be derived from由…得到
be capable of能够
be characterized by以…为特征
be combined with与…结合
be concerned about关心，挂念
be coupled with与……配合
be crowded with挤满，拥塞