_______ his return from America, he got down to his research.

—Were all the supplies for the people carried to the flood-stricken areas?—No,      only some of them      nearly all the roads there cut off.

_____ more than 100 million references to the word“tuhao” on social media since early September．

I can well remember that there was a time _____ a deep blue sky,  the song of the birds,  moonlight and flowers could never have kept me spellbound. 

Can you believe that in ____ a rich country there should be ___many people.