How to balance the government's budget without raising taxes is a ______problem.

 I think nobody makes  _______ contributions to the company than him.

My wife cares more for new clothes than anything else in the world, so she is very _______ about what she wears.

The college entrance exam is ____ important to the student, and it’s also challenging. 

．People like taking photos because photos are the _______ of youth and history and can remind us of many happy scenes.