It is reported that young visitors get more out of a visit if they focus on 25 nine objects.
答案：(C) no more than
【句型】no more than + 數字，表示「不超過……」，符合「聚焦在不超過九件展品上，能讓年輕遊客收穫更多」的語意。no better than（不比……好，語意不合）、no less than（不少於，語意相反）、no sooner than（一……就……，用於時間句型）都不符合。
四個選項都是 no 加一個比較級的組合，長得極像，中文又都能說成「不比……更」，你會憑語感挑一個。
先看整句在講什麼：young visitors get more out of a visit if they focus on ______ nine objects（如果只專注在______九件作品，年輕的參觀者收穫更多）。前一段剛講過看太多會累，這一句給的是一個上限的建議，所以空格要的是「不超過、只有」——no more than 就是這個意思，等於 only，重點在強調數量少。填進去讀成 focus on no more than nine objects（只專注在九件作品上）。
no less than（不少於，等於「多達」）方向剛好相反，填進去會變成「多達九件」，與整段勸人少看的建議矛盾，這一組尤其要小心；no better than 是「跟……一樣糟」，用來評價好壞，不是講數量；no sooner than 不是成立的組合，成組的說法是 no sooner ... than ...（一……就……）。
no more than（只有、不超過，等於 only）、no less than（多達、不少於）、no better than（跟……一樣糟）、no sooner ... than ...（一……就……）、get more out of（從……得到更多）、focus on（專注於）。
Young visitors to museums often complain about having museum feet, the tired feeling one gets after spending too much time in a museum. A case of museum feet makes one feel like saying: "This is 21. I could have done the painting myself. When can we sit down? What time is it?" Studies of museum behavior show that the average visitor spends about four seconds looking at one object. For young visitors, the time span can be 22 shorter.
Children are more interested in smells, sounds, and the "feel" of a place than looking at a work of art. If they stay in a museum too long, a feeling of boredom and monotony will build up, leading 23 to impatience and fatigue.
To 24 museum feet, try not to have children look at too many things in one visit. It is reported that young visitors get more out of a visit if they focus on 25 nine objects. One and a half hours is the ideal time to keep their eyes and minds sharp, and their feet happy!