跟不上功課cannot: cannot =can not. catch: vt. (caught; caught) 1.捕捉;逮著 ...up: adv. (superl. uppermost ) 1. ...one: Once one is one. 一乘一等于 ...cannot catch up with the ranks: 跟不上趟兒下載手機詞典可隨時隨地查詞查翻譯