推測用法
GWD17-38
http://www.formosamba.com/phpBB3/viewtopic.php?t=10853
All Y chromosomes in existence today are descended from a single ancestor’s who is thought to have lived about 140,000 years ago.
A. a single ancestor’s who is thought to have lived
B. a single ancestor’s who was thought to live
C. a single ancestor whom it is thought had lived
D. the Y chromosome of a single ancestor who is thought to have lived
E. the Y chromosome of a single ancestor whom it was thought had lived
ans: D
SC大全987-325
325.Geologists believe that the Bering land bridge, over which human beings are thought to have first entered the Americans, disappeared about 14,000 years ago when massive glaciers melted and caused the sea level to rise several hundred feet worldwide.
(A) are thought to have first entered
(B) were thought first to enter
(C) were thought at first to enter
(D) are thought of as first entering
(E) were thought to first enter
ans:(A)