请教专家老师：

  My cousin, Harry, keeps a large curiously-shaped bottle on permanent display in his study. Despite the fact that the bottle is tinted a delicate shade of green, an observant visitor would soon notice that it is filled with what looks like a thick, grayish substance. If you were to ask Harry what was in the bottle, he would tell you that it contained perfumed mud. If you expressed doubt or surprise, he would immediately invite you to smell it and then to rub some into your skin. This brief experiment would dispel any further doubts you might have. The bottle really does contain perfumed mud. How Harry came into the possession of this outlandish stuff makes an interesting story which he is fond of relating. Furthermore, the acquisition of this bottle cured him of a bad habit he had been developing for years.

1）为什么不是is tinted with ？any further doubt 单数也可以吗？

2）were to - 书上说：这里表示过去预计发生并且发生了的事情 - 没有懂什么意思？这里是不是对将来的虚拟if you were to do = If should do = if you did，这3者含义有差别吗？是不是were to表示概率最低，最不可能？

3）he would tell you that it contained - 为什么用过去时态contained - 而不是一般现在时contains 呢？另外麻烦老师讲解一下had been developing 和 had developed含义差别？完成时可以吗？