Zen Master Dogen instructed,

These days, many people who are learning the Way listen to a talk on the dharma, and above all want their teacher to know that they have a correct understanding and want to give good replies. This is why the words they listen to go in one ear and out the other. They still lack bodhi-mind and remain self-centered.

First of all, forget your ego and listen quietly to what others say, and later ponder it well. Then, if you find some faults or have some doubts, you may make criticism. When you have grasped the point, you should present your understanding to your teacher. Waiting to claim immediate understanding shows that you are not really listening to the dharma.

Dogen also instructed,

Students of the Way, when you practice with a certain teacher and learn the dharma, you should listen thoroughly again and again until you completely understand. If you spend time without asking what should be asked, or without saying what should be said, it will certainly be your own loss. Teachers always await questions from their disciples and give their own comments. You should ask again and again to make sure even of things that you have already understood. Teachers also should ask their disciples whether they have really understood or not, and thoroughly convince them of the truth of the dharma.