单项选择题It can be inferred from the passage that the author assesses the truth about opaque-2-maize in that ______.
单项选择题We learn from the first paragraph that ______.
单项选择题The Japanese staff complained to the American manager because ______.
单项选择题The author provides a sustained argument to support the assertions that ______.
单项选择题The primary purpose of the passage is to discuss ______.