________ thousands of Chinese students，Chuck has vast experience in the Chinese class.
| A．Having taught | B．Taught |
| C．Teaching | D．To have taught |
It is usually warm in my hometown in March, but it ________ be rather cold sometimes.
| A．must | B．can | C．should | D．would |
You can never be ________ when crossing the street．
| A．very careful | B．too careful |
| C．carefully enough | D．enough careful |
________, you need to give all you have and try your best．
| A．Being a winner | B．To be a winner |
| C．Be a winner | D．Having been a winner |
Before Sally left home, her mother kept telling her to ________ her manners at the party.
| A．notice | B．care | C．mind | D．observe |
She has ________ that I find it hard to believe anything bad of her.
| A．so a lovely face | B．so lovely a face |
| C．such lovely a face | D．such lovely face |