题目

Do you often walk to school? Do you often ride your bike to school? It may be a good experience (经历) for you.It was a 【1】 (rain) day. About fifty students, from Cal Young Middle School in the US 【2】 (ride) their bikes to school. They 【3】 thirteen years old. On October 【4】 (four), they joined International Walk and Bike to School Day. Teachers at school asked kids 【5】 (use) their feet to get to school.“We know walking and biking to school are sometimes difficult to a lot of kids. It may take them thirty 【6】 (minute), or even more time, but it's good for health and 5．如图，数轴上点A表示的数是-1，原点O是线段AB的中点，∠BAC=30°，∠ABC=90°，以点A为圆心，AC为半径画弧，交数轴于点D，则点D表示的数是（　　）A．$\frac{2\sqrt{3}}{3}-1$B．$\frac{2\sqrt{3}}{3}$C．$\frac{4\sqrt{3}}{3}$D．$\frac{4\sqrt{3}}{3}-1$