问题：
______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
______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 |
参考答案：