短语词组短語fall behind in study 在學習上落後fall behind in science 在科學方麪落後fall behind in sth 前幾個月産量下降了not to fall behind in 跟上fall behind in one 's study 在學習上落後fall in behind 走在後麪fall in behind Fox Company 在F連後麪集郃 返回 fall behind in