如图所示的四种情景中，所用杠杆属于费力杠杆的是 [ ]
A.
B.
C.
D.
答案：D
In recent years, many children are made ______what they are not ________.
A．to do; interested in
B．to do; interested
C．do; interested
D．do; interested in
企业排出大量污水的行为属于（）。
A.生产的负外部性
B.消费的负外部性
C.生产的正外部性
D.消费的正外部性
