For example: Your instructor wants to go right at the next crossing. He tells you in German language: “We want to go the next street right, you have to break first on about 20 km/h, then you take the second gear and leave the clutch before the crossing”. The interpreter needs to listen He needs time for processing the information and for translation, too. It again takes time to tell you the information. And it takes time until you process the information. In the most cases you passed the crossing before you know what to do. In addition to that your instructor can´t support you during the process, cause the interpreter did not finish the translation.
If you don´t understand your instructor, just go on and ask him. If you pass the crossing he want to turn, you go another way, but nothing is happening. If you stop in the middle of a street for asking him, it can be very dangerous. Cars are also behind you and don´t expect you will stop without a sign. In the exam it is very important for you, to understand the examinator, so you can practice that in your lessons.