1.As soon as he saw us, he picked up a long pipe which was covered with coins and opened one of the baskets.?他一见我们，就拿起了一个长长的上面镶有硬币的管乐器，并掀开了一个筐的盖子。

be covered with翻译成镶原因是硬币无法铺满在管乐器上的。

2.It rose out of the basket and began to follow the movements of the pipe.?movements?词典说它[U, C]。为什么这里要用复数？

movements表示具体的运动活动

3.It obviously could not tell the difference between Indian music and jazz!?difference?词典说它[U, C]。为什么不用复数？

difference表示抽象区别差别不同。

英文原文：

As we had had a long walk through one of the markets of old Delhi, we stopped at a square to have a rest. After a time, we noticed a snake charmer with two large baskets at the other side of the square, so we went to have a look at him. As soon as he saw us, he picked up a long pipe which was covered with coins and opened one of the baskets. When he began to play a tune, we had our first glimpse of the snake. It rose out of the basket and began to follow the movements of the pipe. We were very much surprised when the snake charmer suddenly began to play jazz and modern pop songs. The snake, however, continued to 'dance' slowly. It obviously could not tell the difference between Indian music and jazz!

参考译文:当我们穿过旧德里的市场时走了很长一段路, 我们在一个广场上停下来休息. 过了一会儿, 我们注意到广场的那一边有一个带着两个大筐的耍蛇人, 于是就走过去看看. 他一见我们, 就拿起了一个长长的上面镶有硬币的管乐器, 并掀开了一个筐的盖子. 当他开始吹奏一支曲子时, 我们才第一次看到那条蛇. 它从筐里探出身子, 随着乐器的摆动而扭动. 当耍蛇人突然又吹奏起爵士乐和现代流行乐曲时, 我们感到非常惊奇. 然而那蛇却还是缓慢地 “舞动” 着. 显然, 它分辨不出印度音乐和爵士乐!