It is uncertain________side effect the medicine will bring about，although about two thousand patients have taken it.
| A．that | B．what |
| C．how | D．whether |
Everyone in the class is expected to________in the discussion.
| A．participate | B．attend | C．donate | D．declare |
Please post this letter in the post office nearby, and ______, I will get two tickets in the train station.
| A．in meantime | B．on the meanwhile | C．in meanwhile | D．in the meantime |
Many people are not________the danger of their children's bad habits, which lead to failing to make their dreams come true.
| A．well aware to | B．very aware of | C．aware that | D．well aware of |
A family of five is really a heavy burden, so we all have to work hard to________.
| A．find out | B．work out | C．help out | D．carry out |
Such animals like dinosaurs died out because they couldn’t _____ to the change of the climate.
| A．suit | B．keep | C．adapt | D．switch |