careless/'kεəlɪs/

1.adjective [+person] [ worker] 
(negligent) 粗心的

2.adjective [+driving] 
疏忽的

3.adjective [+mistake] 
疏忽造成的

how careless of me!
我真是太不小心了!
it was careless of him to let the dog out
他真不当心,把狗放了出去
to be careless with sth
 [+money,resources] 对某物很随便
to be careless of sth
 [frm] 不顾某物