Xinjiang is one of the areas sandstorms happen most often, results from a dry climate, vast desert and a strong wind.
--- Did you return the book you borrowed from Tom? --- Yes, I gave it to him ______ I saw him.
You _____ have bought the book for me, but thank you all the same.
I forget where I saw the skirt, otherwise I _______ you the shop now.
The fact has worried people _______ the number of the deaths is still increasing.
Either you or he _______ to give them a lecture tomorrow.