老师好！

请问2022年高考英语乙卷的短文改错的两个句子：

1. We all know that cycling is a greatly exercise.

此句，greatly改为great，请问exercise是可数的吗？

比较牛津例句：Swimming is good exercise. 游泳是有益的运动。

2. Whether you ride a bicycle, you don’t use petrol. So they are not producing carbon dioxide and not cause air pollution.

此句，they改成you，cause改成causing。请问they可以不改吗？因为“语境照应”，就像：

https://www.cpsenglish.com/question/47374

You’re going to need to set aside about three months to acquire a U.K. work visa, but there’s never a guarantee that you’ll succeed in getting one and they’re not cheap to apply for.

以及，

https://www.cpsenglish.com/question/51125

That’s why I love going to musicals because it’s the perfect combination of song, dance and theater.