Now I regret ______ those weight-loss pills.
| A．took | B．taking | C．taken | D．to take |
The research is so designed that once _______ nothing can be done to change it.
| A．begins | B．having begun | C．beginning | D．begun |
“What do you think made Mary so upset?” “_______ her new bike.”
| A．As she lost | B．Lost | C．Losing | D．Because of losing |
“How do you deal with the disagreement between the company and the customers?” “The key ______ the problem is to meet the demand ______ by the customers.”
| A．to solving, making | B．to solving, made | C．to solve, making | D．to solve, made |
The boy wanted to ride his bicycle in the street, but his mother told him ______.
| A．not to | B．not to do | C．not do it | D．do not do |
John wanted to ride his bike in the street but his uncle told him _____ .
A. not to B. not do B. not do it D. do not to