______ at the door before entering please.
| A．Knocked | B．Knock | C．Knocking | D．To knock |
The girl was so happy to find ______ in the garden.
| A．a variety of flowers | B．a variety of flower |
| C．varieties of flower | D．variety of flowers |
It’s obvious that his ______ to the problem is wrong, so we’d better try another way to solve it.
| A．way | B．means | C．approach | D．intention |
Peter phoned to say they had arrived safely, so put your mind ______.
| A．with ease | B．by heart | C．in peace | D．at ease |
. There are many mistakes in his essay, ______his failure.
| A．which results | B．leading to | C．led to | D．that led to |
. He regretted______ to the lecture the day before.
| A．not going | B．not to go | C．not have gone | D．to not going |