5月24日，在2008年中国田径公开赛男子110米栏决赛中飞人刘翔以13秒18夺冠军．请你运用所学知识回答问题．当刘翔一听到发令枪响时，立即起跑．该反射活动的途径是（　　）

①耳 ②传出神经 ③传入神经 ④大脑 ⑤神经 ⑥脊髓 ⑦肌肉．

A．①②③④⑤⑥⑦

B．①③④⑤⑥②⑦

C．①③②④⑤⑦⑥

D．②④①③⑦⑥⑤

• (A) 条件(1)充分，但条件(2)不充分．
• (B) 条件(2)充分，但条件(1)不充分．
• (C) 条件(1)和(2)单独都不充分，但条件(1)和条件(2)联合起来充分．
• (D) 条件(1)充分，条件(2)也充分．
• (E) 条件(1)和条件(2)单独都不充分，条件(1)和条件(2)联合起来也不充分．

During July, a mail order retailer received 3,300 order for amounts less than $100, and 1, 100 orders for amounts of at least $100. What was the average size of an order in July
(1) The gross sales from the orders less than $100 equaled the gross sales from the orders greater than $100.
(2) The orders for less than $100 account for a total of $134,000 in gross sales.