There are four shi ( 是 ) sentences below in Chinese in brackets, and their translation as well. Which shi ( 是 ) is translated into “be”? ( )
A.
Purple belonged to the emperor because of its associations with the north star.
B.
It is a closed residence with only one gate leading to the outside
C.
The Forbidden City stands as the largest complex of palace buildings anywhere in the world
D.
Hong Kong-Zhuhai-Macao Bridge, the world ’ s longest sea bridge, was opened on 23.