Ben， is physics your favorite subject？
Yes， and it is important one．（ ）
A．aB．theC．an
Tina， is your father a teacher？
Yes， he is． He ___________ English for nearly 20 years．（ ）
A．is teachingB．teach
C．has taught
Aizhai Great Bridge ___________ in March 2012 and it is one of the highest bridges in Asia．（ ）
A．was builtB．builtC．is built
Please ___________ the rubbish into different litter bins according to the signs．（ ）
A．putsB．putC．to put
The world is changing with every minute， and China___________ with every minute，too．（ ）
A．is changingB．had changed
C．changed
___________ does your mother go to the supermarket？
Once a week．（ ）
A．How oftenB．How longC．How far