What does the underlined word “alter” in paragraph 3 mean?

(单选题)We spent several days ______ all related reference materials (单选题)______ we persist in carrying out the open-door policy, we w (单选题)He seldom smokes, ______? (单选题)I propose you ______ finish this project as soon as possible (单选题)Tom was ______ to tell the truth even to his parents. (单选题)Lucy got a promotion in her company, ______ was a big surpri (单选题)It is common ______ to eat less when people are sick. (单选题)She ______ some English before she started school. (单选题)My grandmother said she didn’t think she could ever get used (单选题)As we know, a large quantity of wine ______ in Bordeaux.