Passage One
26.
A. They were possibly caused by man.
B. They were mostly caused by volcanoes.
C. They were certainly caused by nature.
D. We know nothing about their causes.
27.
A. Afraid.
B. Excited.
C. Curious.
D. Indifferent.
28.
A. Copper and iron.
B. Copper and tin.
C. Iron and tin.
D. Copper and zinc.