规则可分为正式的和非正式的。下列属于非正式的规则有[     ]

①上食堂打饭时应排队

②红灯停

③穿着要整洁

④商品有缺陷可以退换

⑤公交车上给老弱病残孕让座

A．①②③

B．①③⑤

C．①③④⑤

D．①②③④⑤

____________ many times, but he still couldn’t understand it.

A．Though he had been told

B．Having been told

C．Having told

D．He had been told