68.（ ）

(单选题)It is generally accepted that ______ boy must learn to stand (单选题)In the author’s view, the new vaccine production method seem (单选题)Which of the following is true according to the passage? (单选题)The foremost reason why the egg-based method is defective li (单选题)What step is essential to the traditional production of flu (单选题)The moon-landing is mentioned in the first paragraph to illu (单选题)Which of the following is NOT true? (单选题)In analyzing a problem we should do all the following except (单选题)By referring to Sam’s broken bicycle, the author intends to (单选题)A suitable title for this passage would be ______.