Read and choose. (读句子，选择相应的图片)

1. Look at the rainbow in the sky (天空). [ ]

2. 一Do you like squirrels? 

    一Yes, I do. [ ]

3. We go to our school by taxi.[ ]

4. 一 Susan, can I have strawberries? 

    — Sorry?We don't have strawberries. [ ]

触发器有两种级别：（）和（）。