The research on the new bird flu virus vaccine ischallenging and demanding Who do you think can do the job—____ my students have a try

The little girl couldn’t ________ the problem. She wasn’t ________ clever.

The headmaster will __________ a speech tothe visiting foreign guests this afternoon

The man used what hehad his wife a diamond ring.

Next month we’re going somewhere interesting as soon as the holiday _____.