______(80)
A.a
B.an
C.the
D.this

A.contact
B.talk
C.keep touch
D.stay in touch

Undersea vehicles __________.
A.make direct observations of the ocean floor
B.have the same limitations that divers have
C.are very slow to respond
D.are too small for a man to fit inside

A.the more
B.more
C.the most
D.more and more

A.use
B.downloading
C.access
D.approach

A.running
B.clap
C.click
D.tick

According to the passage, all of the following are true about tidal waves EXCEPT that ________.
A.they are the same as tsụnamis
B.they refer to the same phenomenon as seismic sea waves
C.they are caused by sudden changes in high and low tides
D.this terminology is not used by the scientific community

From the expression "on record" in the last paragraph, it can be inferred the tsunami that accompanied the Krakatoa volcano ________.
A.might be the greatest tsunami ever
B.occurred before efficient records were kept
C.was not as strong as the tsunami in Lisbon
D.was filmed as was happening

A main difference between tsunamis in Japan and in Hawaii is that tsunamis in Japan are more iikely to ________.
A.come from greater distances
B.arrive with little warning
C.originate in Alaska
D.be less of a problem

Although he was very tired, he agreed to help me with my homework.
A.Tired as he was, he agreed to help me with my homework.
B.Despite being very tired, but he agreed to help me with my homework.
C.Tired though he was, but he agreed to help me with my homework.
D.As tired as was he, he agreed to help me with my homework.