The United States minted about 857 million silver-colored “Susan Anthony” dollars between 1979 and 1981, but the coin proved unpopular because it looked and felt too much like a quarter.

1. The United States minted about 857 million silver-colored “Susan Anthony” dollars between 1979 and 1981, but the coin
2. About 857 million silver-colored “Susan Anthony” dollars were minted as coins in the United States between 1979 and 1981 but
3. About 857 million silver-colored “Susan Anthony” dollars that were minted between 1979 and 1981 in the United States
4. About 857 million silver-colored “Susan Anthony” dollars that the United States minted between 1979 and 1981
5. Between 1979 and 1981 the United States minted about 857 million silver-colored “Susan Anthony” dollars, which

prove可以表主动的~

用被动态反而不好了,谁是施动者呢?

Plus:查了一下牛津

P1192:

The old methods proved best after all;

The task proved (to be) more difficult than we had thought.