At a rough estimate, Nigeria is __________ Great Britain.
| A．twice big as | B．as twice big as |
| C．three times the size as | D．three times the size of |
The student corrected his paper carefully, _______ the professor's suggestions.
| A．follow | B．following | C．followed | D．being followed |
He went from door to door, _______ waste papers and magazines.
| A．gathering | B．gathered | C．gather | D．being gathered |
. _______ the office, the foreign visitors were shown round the teaching building.
| A．Having shown | B．Showing | C．Has shown | D．Having been shown |
With winter _______ on, it's time to buy warm clothes.
| A．came | B．comes | C．come | D．coming |
Deeply _______, I thanked her again and again.
| A．being moving | B．moved | C．moving | D．to be moved |