1、Learn new words and new sentences

T :the tree is big, tall and old now, but the tree was thin and short and young then ,and the butterflies are beautiful now, the butterflies weren't beautiful then

刚才出示这么几个词，我们来小结一下，表示现在我们可以用 is, was.其中is用于单数，are用于复数，两个以上我们就叫复数。表示过去我们用was和were, was用于单数，were用于复数。

还有，表示否定我们可以用wasn't 和weren't. wasn't是was 的否定形式， 也就是was not, 而were not的缩写形式就是weren't.

Read after me. Was, was, wasn't wasn't, were were, weren't, weren't.

Step 4: Summary: thank you