68. The researchers’ conclusion was based on a study of the Arican elephant’s .
(A) DNA
(B)height
(C) weight
(D)population

64.what can we know about the author ‘s father after his ship was attacked ? (A) he lost his arm (B)he repaired the engines (C) he managed to take a lifeboat (D)he was the last to leave the ship

65what is the passage mainly about ? (A) a group of forgotten heroes (B)a book describing a terrifying battle (C)a ship engineer’s wartime experience (D)a merchant’s memories of a sea res cue

66. C Arecent study of ancient and modern elephant has come up with the unexpected conclusion that the Arican elephant is divided into two distinct (不同的 )species The discovery was made by researchers at York and Harvard University when they were examing the genetic relationship between the ancient woolly mammoth and mastodon modern elephants—the Aian elepphant, Arican forest elephant, and Arican savanna elephant. Once they obastain DNAsequences（序列）from two fossils（化石）,mammoths and mastodons, the team comparted them with DNAfrom modern elephants. They found their amazement that mordern forest and savanna elephants are as distinct from each other as Aian elephants and mammoths. The scientists used detailed genetic analysis to prove that the Arican savanna elephant and the Arican forest elephant have been distinct species for several million years. The divergence of the two species took place around the time of the divergence of Aian elephants and woolly mamm oths. This result amazed all the scientists. There has long been debate in the scientific community that the two might be separate species, but this is the most convincing scientific evidence so far that they are indeed different species. Previously, many naturalists believed that Arican savanna elephants and Arican forest elephants were two populationgs of the same species, despite the elephants’ significant size differences. The savanna elephant has an average shoulder height of 3.5 metres while the forest elephant has an averate shoulder double the weight of the forest elephant.Bt the fact that they look so differrent does not neccssarily mean they are different species. However the prooflay in the analysisi of the DNA Afried Roca, assita nt professor in the Department of Aimal Sciences at t he University of Illinois, said, “We now have to treat the forest and savanna elephants as two difficult units for conservation purpose. Since 1950, all Aican elephants have been conserved as one species. Now that we know the forest and savanna elephants have been distinct animals, the forest elephant should become a bigger priority（优先）for conservation purposes.” One of the fossiles studied by the researchers is that of . (A) the Aian elephant (B)the forest elephant (C)the savanna elephant (D)the maslodon elephant

67. The underlined word “divergence” in Paragraph 4 means “ .” (A) evolution (B)exhibition (C) separation (D)examination

69. What are Afred Roca’s words mainly about? (A) The conservation of Aican elephant (B)The purpose of studying Aican elephant (C) The way to divide Aican elephants into two units (D)The renson for the distinction of Arican elephants

70.Which of the following can be the best tille for the passage? (A) Naturalist’Bliefs about Elephants (B)Aazing Experiments about Elephants (C)A Unexpected Finding ahout Elephants (D)ALong Scientifif Debate about Elephants

21. Every evening after dinner, if not ______ from work, I will spend some time walking my dog. (A). being tired (B). tiring (C). tired (D). to be tired

22. Most Americans would prefer to keep their problems ______ themselves, and solve their problems ______ themselves. (A). to; by (B). by; to (C). for; to (D). in; on

23. When he ______ the door, he found his keys were nowhere. (A). would open (B). opened (C). had opened (D). was to open

24. I can ______ be a teacher. I’m not a very patient person. (A). seldom (B). ever (C). never (D). always