“Simon wants to know if the Class 3 students___hiking tomorrow.” “Yes, but if it _____ , they’llvisit the museum instead.”

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

Why not ____ help when you were in trouble

periment shows that proper amounts ofexercise, if regularly, can improve our health.

She supports a culture ____ people believe they canmake anything happen