Fighting an artificial greenhouse effect seems to be the greatest of environmental challenges, ________？

_____Millie and you like walking after super?

—The street is too bad，isn’t it?—_______,_______it’s a bit too crowded.

---Why do you think he can succeed?---He believes in himself, ____ is the most important, I think.

 —Can Jenny speak English?—_________, but he can speak Chinese.