Essentially, yes. The 'rule' is that the subordinator "that" cannot normally be omitted if the relativised element is subject of the relative clause, but in other other functions it can. With the odd minor exception, in contexts other than this, "that" is grammatically optional.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
Essentially, yes. The 'rule' is that the subordinator "that" cannot normally be omitted if the relativised element is subject of the relative clause, but in other other functions it can.
With the odd minor exception, in contexts other than this, "that" is grammatically optional.