Comparison may make something appear more beautiful than it is when alone.
| A．to see | B．seeing | C．is seen | D．seen |
Bad habits, _______ formed, are difficult, and sometimes impossible to shake off.
| A．before | B．once | C．until | D．unless |
The monument was built in honor of the explorer who was believed _____ the river.
| A．to discover | B．to have been discovered |
| C．to have discovered | D．having been discovered |
________ blood if you can and many lives will be saved.
| A．Given | B．Give | C．Giving | D．To give |
_______ the morning of my mother’s birthday, I usually help my mother do some housework.
| A．On | B．In | C．During | D．At |
You ‘d better not phone the manager between 7 and 8 tomorrow evening; he _____ an important meeting then.
| A．will have | B．would have | C．will be having | D．will have had |