It is pedestrian-friendly and car _______. The city is experimenting with a network of electric ______________ pocars.

A number of people have been experimenting during the 20s with________________________________.

Animal conservationists strongly disapprove ______ experimenting on animals. A: of B: / C: about D: against

Which of the following does the author suggest to a person who wants to be a teacher? A: Watching teachers at work, or organizing students' spare time activities B: Joining a future teachers' club, talking with job advisors, or working with children C: Preparing and correcting homework, experimenting with teaching methods and equipment D: Planning lessons, or attending teachers' meetings