1. Use equal-length toothpicks to form the rectangular pattern shown in the figure. If the length of the rectangle is 20 toothpicks long and the width is 10 toothpicks long, then the number of toothpicks used is
A. 200
B. 410
C. 420
D. 430
1. D First, look at the number of toothpicks horizontally: there are 11 rows, with 20 toothpicks in each row, totaling 220; then look at the vertical direction: there are 21 rows, with 10 toothpicks in each row, totaling 210.
Therefore, the total number of toothpicks is $220+210=430$ (toothpicks).
So the answer is D.