_________ he was exercising in the park yesterday morning, he found a purse under the tree.
A：While
B：Before
C：After
蛇的种类多种多样，有眼镜蛇、五步蛇等，是生物多样性的表现，生物多样性不包括
下列词语中划线的字读音都正确的一项是（ ）
