Of the two types of sentence stress, sense stress shows contrast, while logical stress shows meaning.（）

判断题The back-chaining technique means the students repeat a sentence after the teacher, starting from the end part of the sentence and moving towards the beginning.（）

判断题A phoneme is the smallest distinctive sound unit, incapable of change in different phonetic environments.（）

判断题Consonants vary depending on where and how the air stream gets through, the place and movement of the tongue, and also whether the voice is used or not.（）

判断题Vowels are formed mainly by the position of the tongue and, secondarily, by the shape of the lips and movement of the jaw.（）

判断题The vowel is produced without (or with little) restriction during its production and is always voiced.（）