I tried hard to _______ a mental picture of what might have happened, but however hard I tried, I simply couldn’t _______ it.

You look worried. ________ — My grandpa is ill in hospital.

Could you tell me

Without the development of the Internet, Taobao and Tmall______$ 5.7 billion in sales on 11 November, 2013.

早上老师上课时，同学们应该说：________。