I suggest thinking up concept check questions before the lesson and jotting them down somewhere. Ask the students a question closely related to the target concept. For example, if you are working on a third conditional sentence like this: "I would have done my homework if I had had enough time", your concept checking questions could be these: Did you do your homework? Did you have enough time? If you're checking the understanding of instructions which say: "Guess your partner's answers to the true or false questions below", you could ask: Do you need to speak to your partner at this stage?
Here is another example... When teaching the modal auxiliary should for giving advice, You might ask the following concept questions:
Remember, our concept checks are not really meant to trick or fool students but for them to just demonstrate that they have understood the new language or skill.
- Is Bob in bed now?
- Is Bob sick?
- Does Mary think it is okay for Bob to stay in bed?
- Does Mary want Bob to get some rest?
Avoid asking Do you understand? and have fun concept checking!
I hope this helps.