First, multiple-choice questions.

1. The following statement is true ()

① Rational number can be an integer or a fraction ② Rational number can be a positive number or a negative number.

Integer can be positive or negative. The score can be positive or negative.

A 1 B 2 C 3 D 4

2.a and B are rational numbers, and the positions of their corresponding points on the number axis are shown in the following figure:

Put a, -A, b and -B () in descending order.

a-B