Such animals as South China tigers are believed_______, for we’ve had no track of them for ages.
A、becoming extinct
B、to become extinct
C、to have been extinct
D、having been extinct
A、becoming extinct
B、to become extinct
C、to have been extinct
D、having been extinct
【参考答案及解析】
本题考查时态和believe的用法 C选项，当believe为被动语态时，后面习惯接不定式。根据后半句“for we’ve had no track of them for ages”判断，时态应为现在完成时。extinct“绝种的，灭绝的”。综上，C选项正确。 A选项，与题意不符，故排除。 B选项，与题意不符，故排除。 D选项，与题意不符，故排除。 故正确答案为C 项。
本题考查时态和believe的用法 C选项，当believe为被动语态时，后面习惯接不定式。根据后半句“for we’ve had no track of them for ages”判断，时态应为现在完成时。extinct“绝种的，灭绝的”。综上，C选项正确。 A选项，与题意不符，故排除。 B选项，与题意不符，故排除。 D选项，与题意不符，故排除。 故正确答案为C 项。