A．A good teacher can teach several subjects.
B．A good teacher can involve students from different fields.
C．A good teacher should invite more experts to the class.
D．A good teacher should have background knowledge of several subjects.
A．Because they are poor.
B．Because they are in trouble with the law.
C．Because conditions favored the old life are gone forever.
D．Because they don't want to adopt the white man's ways.
A．narrow strip of land.
B．A manufacture bridge.
C．A narrow strait.
D．An island.
A．More than 300.
B．Less than 300.
C．Less than 200.
D．At least 200.