现在与过去对比表达
这个单元把"以前"和"现在"放在一起说:Before/In the past（过去），now（现在）。常见句式如 There was no library before, but now there is a big one（以前没图书馆，现在有个大的）。核心就是过去时和一般现在时在同一段里交替使用，讲清变化。
难点在于两种时态在一篇短文里来回切换:讲"以前"用过去式，讲"现在"用现在时，学生容易时态串味。突破方法:动笔前先画一条时间线，把"过去列"和"现在列"的动词分别标好时态再写。
💬 典型例句4 则
There was no library before, but now there is a big one.（以前没有图书馆，现在有一个大的。）——There was（过去）与There is（现在）对比，讲清变化
In the past, I couldn't swim, but now I can swim very well.（过去我不会游泳，现在我游得很好。）——couldn't（过去）对now can（现在），突出能力的今昔差别
Before, she went to school on foot, but now she goes by bike.（以前她走路上学，现在她骑车去。）——went（过去时）与goes（一般现在时）在同一句交替，说清习惯变化
There were only a few houses here before, but now there are many tall buildings.（以前这里只有几间房子，现在有许多高楼。）——There were对There are，用复数be动词的过去与现在对比多与少的变化
🌟 学以致用 · 解决生活中的问题
写"我的家乡变化":In the past, there were few metro lines in Hangzhou. Now there are many, and it's much easier to travel.——杭州这些年的变化，孩子亲眼见过，最有话说。
写"我的家乡变化":In the past, there were few metro lines in Hangzhou. Now there are many, and it's much easier to travel.——杭州这些年的变化，孩子亲眼见过，最有话说。