Catch up 赶上;与别人看齐 I'd love to go with you but I've got some catching up to do. 我也想跟你一起去,但我还得先赶进度。
Behind 在后面;落后;忘掉过去。 Look behind you! Something is coming! 看你身后!有东西过来了! I'm behind in my work. 我积压了很多工作。 The accident is behind you now, so try to forget it. 那场事故已经过去了,忘了它吧