Mr. Smith didn’t understand _____ made his son so upset that evening.
The system has been designed to give students quick and easy ________to the digital resources of the library.
—The speaker is a tall man with glasses.—Then it be Mr. Smith, who is short and thin.
About 187 passengers were reported _____ the shipwreck which happened last month.
Once new difficulties ________in your work, it’s always important to use your brains.
--How are your recent trip to Sichuan?—I’ve never had ______ one before.