一般现在时:am/is/are+done The bridge is built every year.
现在进行时:am/is/are+being done The bridge is being built now.
现在完成时:have/has+been done The bridge has been built just.
一般过去时:was/were+done The bridge was built last year.
过去进行时:was/were+being done The bridge was being built in Oct. last year.
过去完成时:had+been done The bridge had been built by the end of last year.
过去将来时:would+be done He said the beidge would be built next year.
一般将来时:will+be done或am/is/are+going to be done The bridge will be built next year.