In your guide, "it" should mean the exact same thing like antecedent.
1//The unskilled workers at the Allenby plant realized that their hourly rate of $4.11 to $4.75 was better than many nearby factory wages.
A> it is in many nearby factories
B> that offered by many nearby factories
So i dont have problem on the first one. I choose B. very clear.
But for the rest of two sentences, i got wrong. I think i am confused on this kind of comparison questions.
Please help me explain a little.
2//Sales of manufactured goods rose to 176 billion in 1993, an amount that is 14 percent more than previous year was.
A>an amount that is 14 percent more than previous year was
B>an amount that is 14 percent higher than the previous year's figure
B is correct.
3//In the 1980's the rate of increase of the minority population of US was nearly twice as fast as it was in the 1970's.
A>twice as fast as it was in
B>twice what it was in
B is correct.