A、 So they can feel its weight.
B、 So they can examine its contents.
C、 So they can guess its age.
D、 So they can admire its beautiful color.

【正确答案】 B

【答案解析】解析：Why does the professor pass the amber around to the students?

A、 How amber changes shape when heated.
B、 How clear amber is.
C、 How common is around the world.
D、 How easily amber can break.

【正确答案】 D

【答案解析】解析：When the professor mentor glass in the talk, what point is he trying to make about amber?

A、 Tropical insects.
B、 Decayed leaves.
C、 Tree resin.
D、 Bird feathers.

【正确答案】 C

【答案解析】解析：What is amber derived from?

A、 Its amber contains numerous fossils.
B、 Its amber is the most durable.
C、 Its amber is opaque.
D、 It is the site of the oldest amber deposits.

【正确答案】 A

【答案解析】解析：Why is the Dominican Republic an important source of amber?

A、 Amber mined from the Appalachian Mountains.
B、 Amber with no imperfections.
C、 Amber containing organic material.
D、 Amber with no inclusions.

【正确答案】 C

【答案解析】解析：What type of amber is probably the most valuable for genetic research?