London's taxis are regarded as ________ best in the world，and New York's yellow taxis came ________ second，according to an annual taxi poll.
| A．the；the | B．the；a | C．/；the | D．the；/ |
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 |
at the photos, illustrations, title and headings and you can guess what the reading is about.
| A． | To look | B． | Looking | C． | Having looked | D． | Look |
I cannot hear the professor clearly as there is too much noise ________ I am sitting.
| A．before | B．until | C．unless | D．where |
Sophia got an e-mail ________ her credit card account number.
| A．asking for | B．ask for | C．asked for | D．having asked for |