1. The probability of drawing at least 1 girl from 3 boys and 4 girls is $\qquad$ .
$$
=1 . \frac{34}{35} \text {. }
$$

Draw a tree diagram, from 7 people, 3 are drawn, there are a total of $7 \times 6 \times 5=210$ ways to draw, among which, the number of ways to draw 3 all being boys is 6, thus, the probability of drawing 3 all being boys is $6 \div 210=\frac{1}{35}$. Therefore, the probability of having at least one girl among the 3 people is $1-\frac{1}{35}=\frac{34}{35}$.