On account of fuel supplies being finite and many people being wasteful, we will have to install ________ solar heating device in our home.
| A．some type of a | B．some types of a | C．some type of | D．some types of |
Remember __________ the book when you have finished it.
| A．putting back | B．having put back |
| C．to put back | D．to have put back |
—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 |
Jiaxing is such a beautiful city that it is well worth __________.
| A．visit | B．visiting |
| C．visited | D．to visit |
You can't imagine the difficulty he __________ into the cold river and saving the drowning girl.
| A．had to jump | B．had jump |
| C．had jumping | D．had jumped |
Lydia doesn't feel like __________ abroad. Her parents are old.
| A．study | B．studying |
| C．studied | D．to study |