忙于做某事的英文：
be busy with sth.

参考例句：

Be Busy at; be doing things;actively engaged
忙于做某事

busy是什么意思：
adj. 忙碌的；忙于···；人来车往的；占线的；纷繁的
v. 忙着做某事
n. 侦探，包打听

Be engaged in; be Busy in
从事于

to sit for business
因公滞留

As Busy as a bee
(象蜜蜂)忙忙碌碌的

Monkey Business
耍些骗人的把戏、捣鬼

depressed business
不景气的生意

sth是什么意思：
abbr. something的缩略词

average sth out(at sth);calculate the average of sth
算出某事物的平均数

be agreeable to sth
欣然同意某事

at/on the altar of sth
因为，为了（值得为之受苦的事）

pretence of sth; false show of sth
假象;假相

see to sth attend to or deal with sth.
照看或处理某事物 。