[紧急求助]英语语法.被动语态中什么时候要加be动词,什么时候不用加be?要怎样判断?

都要加的,A is/are (not) done (by B)。A is/are (not) going to be done (by B)。A will (not) be done (by B)。A has/have/had not been done by B。