84 为什么春天的杨树要飞毛毛呢？

poplar n. 杨树
There is a bench under a poplar tree.
杨树下有一张凳子。
pine n. 松树
There are pine trees along the street.
街道两旁都是松树。
spring n. 春天
There are lots of poplar flowers in the spring.
春天里有很多杨树花。
表示在某个地方有某物，用there be 句型: There is /are + 名词。