Model: sit / stand → Don't sit, please stand.     
1. run / walk → ______________________
2. jump / walk → ______________________ 
3. talk / sing → ______________________  
4. open / close → ______________________ 
5. read / write → ______________________  
6. sing / swim → ______________________

1. 请站在火车一边。
    Please stand _____________ the train.
2. 我不喜欢这条裤子，我喜欢那条。
    I don't like _____________ pants. I like _____________ pants.
3. 火车太有趣了！
    _____________ are so _____________!
4. 我找不到钢笔了，它丢了。
    I can't _____________ my pen. It's _____________.
5. .妈妈和我向火车走去。
    My mother and I _____________ _____________ the train