1.bat可指棒球的“球棒”，板球的“球板”，乒乓球、网球等的“球拍”。
2.bat用作不可数名词时还可指“击球”，用作可数名词时还可指“击球员”。

off one's own bat
靠自己的力量 through one's own efforts
This country was able to win the war off its own bat.这个国家能依靠自己的力量打赢这场战争。

off the bat
〈非正〉立即,立刻 without delay
Speaking off the bat,I'd say you were right.说一句不打草稿的话,我认为你是对的。

I have left my bat at home.我把球拍忘在家里了。
He is a useful bat.他是优秀的击球员。
The cry of a bat is too acute for the human ear to hear.蝙蝠的叫声非常尖细,人类的耳朵听不见。
Neither beasts nor birds would have the bat as their friend, so he was afraid to leave his home.兽类和鸟群都不把蝙蝠当作朋友,因此蝙蝠不敢离开窝。