单选题
At a doctor’s office.
In a biology lab.
At a radio station.
In a lecture hall.
单选题
Automobile safety.
Increasing fuel efficiency.
Electricity-powered cars.
The improvement of car batteries.
单选题
Immigrants to the USA often keep their own ethnic characteristics.
Immigrants to the USA contribute a lot to their adopted land.
Stew has a distinctive flavour.
Americans of German ancestry have made a great contribution to the USA.