d 是should 还是would 亦或是had的缩写？

前几日，曹老师过去说过s 可能是is或者has的缩写，但不会是was的缩写，收获颇丰。

另外请问d是should 还是would 亦或是had的缩写？或是有不缩写的现象（好似was)？

另外，下面这句话中的d是不是would或should都可以？

If a camper was attacked by a bear or something, wed hear about it.

谢谢！

If a camper was attacked by a bear or something, wed hear about it.

本句，d = would，不是 should。