I won’t be able to answer any phone all the afternoon．I_____________ a conference．
| A．am attend | B．was attending |
| C．will be attending | D．will have attended |
Please remember _______ the plants while I’m away.
| A．watering | B．to be watering |
| C．to water | D．being watering |
Please excuse me _______ your letter by mistake.
| A．to open | B．to have opened |
| C．for opening | D．in opening |
After describing the planned improvements, she went on _______ how much they would cost.
| A．to explain | B．explaining |
| C．to be explaining | D．having explained |
The film star walked to his car, ______ a crowd of journalists.
| A．followed by | B．following by |
| C．to follow | D．to be followed by |
_______ on time, this medicine will be quite effective.
| A．Taking | B．Being taken |
| C．Taken | D．Having taken |