FAQs About the word dropping in (on)

突然拜访(某人)

致电(至或致),看到,访问,查看,寻找(出),顺道拜访

扫一边(或扫掉),忽视,鄙视,冷落

dropping in => 坠入, dropping by => 顺道拜访, dropping behind => 落后, dropping back => 回滚, dropping (off) => 下降(关闭),