This problem may lead to more serious ones if ____ unsolved.
| A．left | B．remained | C．keeping | D．making |
I smell something __________ in the kitchen. Can I call you back in a minute?
| A．burning | B．burnt |
| C．being burnt | D．to be burnt |
As the light turned green, I stood for a moment, not ___, and asked myself what I was going to do.
| A．moved | B．moving |
| C．to move | D．being moved |
—Come on, please give me some ideas about the project.
—Sorry. With so much work __________ my mind, I almost break down.
| A．filled | B．filling |
| C．to fill | D．being filled |
— Robert is indeed a wise man.
— Oh, yes. How often I have regretted __________ his advice!
| A．to take | B．taking |
| C．not to take | D．not taking |
Leonardo da Vinci(1452-1519)__________ birds kept in cages in order to have the pleasure of setting them free.
| A．is said to be buying | B．is said to have bought |
| C．had said to buy | D．has said to have bought |