in the heart of Toronto is the Canadian National Tower, is often called the CN Tower for short.
A. Located, where
B. locating, which
C. locating, where
D. located, which
网友回答
A. Located, where
B. locating, which
C. locating, where
(答案→)D. located, which
解析：考查非谓语动词及定语从句。be located in坐落于，在句中作状语；which引导非限定性定语从句，指代前面一句话，选D。