IMO, to train just "a string of techniques" is not enough. You will need to train "many strings of techniques".What he meant is what the OP is referring to: the fact that you will most likely never execute a string of techniques the way you do in class in a predetermined drill, with no resistance.
When you kick, your opponent can
- block with his arm,
- block with his leg,
- move away.
There are 3 possible ways that your opponent may respond. You have to train all 3 outcomes from your opponent's respond.