from time to time意为有时，不时；be different from意为与之不同；come from意为出生于，来自；from door to door意为挨家挨户；from now on意为从现在起，今后；from tip to toe意为彻头彻尾，完全；hear from意为收到某人来信be from意为来自；from then on意为从那时起；from morning till night意为从早到晚。