look up抬头看
观察 She looked up and saw a white rabbit in a coat passing by.她抬起头看见一只穿着外套的白兔经过。
She looked up as I entered the room.我进房间时她抬起头看了看。[探究] look up是固定短语,意为“抬头看”。

[拓展]
(1)look up还可译为“查阅”You can look up new words in a dictionary.你可以在词典中查找生词。
(2)与look相关的短语:
look at看
look after 照顾,照料
look for 寻找
look out 小心,当心
look around 环顾四周
look forward to 期待

fall ti.落下,掉落;倒
观察 Alice fell for a long time, and then she hit the ground.爱丽丝掉了很长时间,然后才落地。
The cat fell into a hole.
这只猫掉入了一个洞里。

探究 fall的过去式为_fell_。常用短语:fall into掉入 fall off 从……滑落
fall asleep入睡fall behind落后,掉队
拓展 fall还可作名词,意为“秋天:落下;瀑布”。We visited the Niagara Falls in the fall of 2015.
我们在2015年秋天参观了尼亚加拉大瀑布。I had a fall (from a horse) and broke my arm.我(从马上)跌下来把胳膊摔断了。