Unless we can find new sources of energy, our life certainly be destroyed .
The phrase "keeps sellers on their toes" in the passage mostly means "______".
Education in many countries is compulsory________the age of 16.
I am sorry I have no time at present to____________________ detail of our plan.
According to critics of globalization, several developed countries have become rich because of
_______ has been a topic of continual geological research.
The Lake District,____________________ was made a national park in 1951, attracts a large number of tourists every year.
______ his brother, Mike is active and friendly.
The pool should not be made so deep______small children can be safe there.
Tom: "___________________ " Mike: "I won't say no!"
The packages___________________ so that it would be easier to carry them.