__________at the door before you enter the office，or you’ll be considered impolite
| A．Knocking | B．Knocked | C．Knock | D．To knock |
Alexander Granham Bell invented ___ telephone in 1876.
| A．/ | B．a | C．the | D．one |
The little boy wishes to be ___.
| A．a Lei Feng | B．the Lei Feng | C．Lei Feng | D．an Lei Feng |
--How do you pay the waitress? ---As a rule, they are paid ____.
| A．by hour | B．by the hour | C．by an hour | D．by hours |
___ is different from that of the 19th century.
| A．New York of the 18th century | B．The New York of the 18th century |
| C．The New York of 18th century | D．New York of 18th century |
Our manager goes to work ___.
| A．in car | B．on car | C．by a car | D．in a car |