Vitamin D helps our bodies make a special chemical,and this special chemical, ____ ,
affects our brains,making us feel happy.
| A．in turn | B．in particular |
| C．in advance | D．in short |
We should be able to do the job for you quickly, ____you give us all the necessary information.
| A．in case | B．so long as |
| C．if only | D．as far as |
— Mrs.Smith,please teach me how to draw on the computer today.
—Oh,no. ____.You have to get familiar with the keyboard first.
| A．It is never too old to learn |
| B．Think twice before you do |
| C．Learn to walk before you run |
| D．One today is worth two tomorrows |
Overpopulation is a terrible threat to the human race.Yet it is probably ____ a threat to the human race than environmental destruction.
| A．no more | B．not more | C．even more | D．little more |
Ladies and gentlemen,welcome to my program.____ me this evening is Dr.Gray.
| A．To join | B．Join | C．Joined | D．Joining |