Pigeon is often considered a（n）________ of peace.
| A．example | B．sign | C．mark | D．symbol |
The old man has expected to see all his children when he was in hospital, but ______ came to see him.
| A．none | B．no one | C．someone | D．anyone |
David apologized for _______to inform me of the change in the plan.
| A．his being not able | B．him not to be able |
| C．his not being able | D．him to be not able |
Jackson returned to Seattle for a while, ______ to Canada, and worked a few jobs there before heading for New York .
| A．moving | B．moved | C．being moved | D．having moved |
We were swimming in the lake _____ suddenly the storm started.
| A．when | B．while | C．until | D．before |
That is the only way we can imagine _______ the overuse of water in students’ bathrooms.
| A．reducing | B．to reduce | C．reduced | D．reduce |