John, look at the time. ______ you play the piano at such a late hour ?
Listen! Do you hear someone for help?
It rained heavily in the south,_______ serious flooding in several provinces.
Mrs. White showed her students some old maps ______ from the library.
Mark ______ have hurried. After driving at top speed, he arrived half an hour early.
People have always been ______ about exactly how life on earth began.