He failed the midterm examination and only then ________how much time he had wasted.
| A．he realized | B．did he realize |
| C．he had realized | D．had he realized |
______ our return, all the students burst into cheers for our excellent performances.
| A．At | B．In | C．On | D．With |
Next door to ours ________, who is no less than eighty.
| A．that lives an old man | B．does an old man live |
| C．lives an old man | D．where lives an old man |
. It is reported that two hotels，_____ are being built in my hometown，will open next year.
| A．they both | B．which both | C．both of them | D．of which both |
. The president spoke at the business meeting for nearly an hour without ___ his notes.
| A．bringing up | B．referring to | C．looking for | D．trying on |
— Why do you want the book so much?
— ____, sir.
| A．Studying | B．Studied | C．Studies | D．To study |