I think the serious pollution is one of the c_____ for most countries

来源：学生作业帮助网编辑：作业帮时间：2024/05/13 06:44:03

I think the serious pollution is one of the c_____ for most countries
I think the serious pollution is one of the c_____ for most countries

I think the serious pollution is one of the c_____ for most countries
circumstances 境况
但如果能填词组的话 common problems更好