31. It’s not easy for experts to ______ H1N1 flu in humans from regular human seasonal influenza.
| A．distinguish | B．separate | C．define | D．recognize |
According to the arrangement, the athletes of our school ________ at the gym for two hours every day.
| A．work out | B．carry out |
| C．take in | D．set aside |
Our government's plan to fight against air pollution will focus on ________ information and handling PM2.5.
| A．expressing | B．representing |
| C．gathering | D．acknowledging |
In fact fuels we burn and plant food we eat ________ their chemical energy in the form of heat.
| A．give in | B．give off |
| C．give away | D．give up |
Don't be so discouraged.If you ________ such feelings, you will do better next time.
| A．carry on | B．get back |
| C．break down | D．put away |
Schools in China are required to ________ at least one “Sports Day” per academic year.
| A．set aside | B．set down |
| C．set out | D．set off |