Marking “Earth Day 2009” with his plan for _____ energy．President Barack Obama on Wednesday called for energy exploration.

I’m always told by my mum never to ______ what should be done today until tomorrow.

Will you come to my party next week—- _____. I’ll fly to Shanghai for a meeting.

Could you take care of my cat _________ I’mon vacation

32．Many experiments_____before the research team was able to get theexact data to carry on project.