题目内容：

 

1.There are always soldiers __________ (守卫) outside the gate of the government buildings.

2.We can __________ (使……满意) our basic wants more easily than in the past.

3.__________ (以，凭借) his efforts, Edison successfully made so many useful inventions.

4.The Chinese government has decided to do further research on that __________ (未知的) areas as soon as possible.