Professor Smith, along with his assistants, _______ on the project day and night to meet the deadline.
| A．work | B．working | C．is working | D．are working |
The traffic on the main streets has a longer green signal thanon the small ones.
| A． | one | B． | this | C． | that | D． | it |
--I feel so nervous about the National English Speech Competition tomorrow.
--________.
| A．I really envy you | B．Glad to hear that | C．Sounds great | D．Take it easy |
Some people care much about their appearance and always ask if they look fine in ________ they are
wearing.
| A．that | B．what | C．how | D．which |
Among the crises that face humansthe lack of natural resources.
| A． | is | B． | are | C． | is there | D． | are there |
An ecosystem consists of the living and nonliving things in an area ________ interact with one another.
| A．that | B．where | C．who | D．what |