A normal lesson should have the all the stages discussed in this unit and the stages should be in fixed order.（）

One function of a language can only be expressed by one...

判断题One function of a language can only be expressed by one structure.（）

The natural order hypothesis is presumed by Krashen to ...

判断题The natural order hypothesis is presumed by Krashen to be the result of the learned system, operating free of conscious grammar.（）

For Krashen, the affective filter is the principal sour...

判断题For Krashen, the affective filter is the principal source of individual difference in second language acquisition.（）