描述过去与现在的变化 — 英语词汇题

词汇题：根据句意和中文提示，用本单元核心词汇补全句子（每空一词）。 1. Time f____ (飞逝) when we are happy. 2. My little brother was s____ (矮的) before, but now he is tall. 3. There w____ (是，过去式) only one small tree in the garden then. Now there are many big trees.