It is said that the early European playing-cards ______ for entertainment and education.
| A．were designed | B．have designed | C．have been designed | D．were being designed |
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 |
Young people may risk ________ deaf if they are exposed to very loud music every day.
| A．to go | B．to have gone | C．going | D．having gone |