7. Let the set $A=\left\{a \mid a=3 k+2, k \leqslant 2000, k \in \mathbf{N}_{+}\right\}, B=\{b \mid b=4 k-$ $\left.1, k \leqslant 2000, k \in \mathbf{N}_{+}\right\}, A \cap B$ contains $\qquad$ elements.
7. 500. Let $c \in A \cap B, c=12k-1 \leqslant 6002$, we get $k \leqslant 500$. 25 , then $|A \cap B|=500$.