New equipment and other improvements reduced the amount of time-from eleven hours in 1982 to six in 1988-needed by workers so that they could produce a ton of steel.
New equipment and other improvements reduced the amount of time—from eleven hours in 1982 to six in 1988—needed by workers so that they could produce a ton of steel.
这句话应该是可以把破折号中间的部分去掉不看 New equipment and other improvements reduced the amount of time needed by workers so that they could produce a ton of steel. 请问a的错误就是因为they是不能指代workers吗?