brush n. 刷子
build vt. 建筑，建立
building n. 建筑物，大楼
bus n. 公共汽车
busy a. 繁忙的
be busy doing sth. 忙着做某事
be busy with sth. 忙于某事
but conj. 但是
not only … but also 不仅……而且……
buy vt. 购买
by prep. 在旁边; 通过
by bus car train ship plane air 乘公共汽车小轿车火车船飞机
by oneself 独自;单独
bye-bye int. 再见
