—Robert is indeed a wise man.
—Oh, yes. How I regretted __________ his advice!
| A．to take | B．to have not taken |
| C．taking | D．not having taken |
On the wall __ two large portraits.
| A．hangs | B．hang | C．hanged | D．hanging |
Sunglasses can ___ us from strong sunlight.
| A．hold | B．prevernt | C．protect | D．make |
His father feels ___ his duty to help others.
| A．this | B．it | C．that | D．what |
I regret ___ harder in the past two years.
| A．not having studied | B．having studied | C．having not studied | D．not being studied |
Tom’t uncle must be an engineer, ____?
| A．mustn’t he | B．can't he | C．isn’t he | D．needn’t he |