－ Henry isn’t quite himself today. He seems to be so tired.－ He said he had worked on his project ________ the whole night.

It is obvious to the students _____ they should get well prepared for their future. [ ]

Not earning enough money this month, I had to ____my expenses. [ ]

Warmblooded animals live an active life even in freezing winter, which helps them to________their normal body temperature.[ ]

What’s the use of this kind of fuel(燃料) — It can make the train __________ fast.