2. sin? A: pronunciation: the square of saiyin a;

3.φ: fai (empty set);

4.{ 1, 2}: pronounced: a set consisting of 1 and 2;

5.{x|x=2k, k∈R}: even set;

6.(a, b): pronunciation: open interval ab;

[a, b]: pronunciation: closed interval ab;

(-∞, a): an interval consisting of real numbers less than a;

7.N+: positive integer set;

8.{ positive integer}: positive integer set;

9.A≤B: read: A is contained in B (A is a subset of B);

B≥A: pronounced as: B contains A(A is a subset of B);

10. The last two readings are: A is proper subset of B.