There are many old trees in our school each about 100 years ago. A. dates back toB. dati

问题补充：

There are many old trees in our school, each about 100 years ago.

A. dates back to

B. dating from

C. dated back

D. which dated to

答案：

A. dates back to

B. dating from

C. dated back

D. which dated to

解析：date from是不及物的，用现在分词，each dating from…相当于and each (tree) dates from…