The first textbooks______for teaching English as a foreign language came out in th 16th century为什么不用TO BE WRITTEN 而用WRITTEN

问题描述:

The first textbooks______for teaching English as a foreign language came out in th 16th century
为什么不用TO BE WRITTEN 而用WRITTEN

这不是显然的嘛,“in th 16th century”在过去啊,“TO BE WRITTEN”表将来啊