(4) 下線部 That の内容
【元の問題文】
次の英文は、中学生のハルカ（Haruka）とALTのスミス先生（Mr. Smith）の対話の一部である。また、図1と表2はハルカがクラスで調査した結果である。
Mr. Smith:Haruka, you look sleepy today.
Haruka:I went to bed at one last night. I was watching videos on my smartphone.
Mr. Smith:Oh, no. How many hours 1 every night?
Haruka:I usually sleep only about six hours.
Mr. Smith:That's not enough for junior high school students.
Haruka:I know. Actually, I did a *survey about smartphones in my class. Look at Graph 1. It shows what students do on their smartphones.
Mr. Smith:Watching videos is the most popular.
Haruka:Yes. Playing games is more popular than sending messages, but it is not as popular as watching videos. Only twelve students use their smartphones for studying, and twice as many students use them for sending messages.
Mr. Smith:What does Table 2 show?
Haruka:It shows how long students use smartphones and how long they sleep. Students who use smartphones for more than three hours sleep 3 than students who use them for less than one hour.
Mr. Smith:That's a big difference. The light from the *screen makes it hard to fall asleep.
Haruka:What did you do when you were a student?
Mr. Smith:When I was a high school student, my family made a *rule. We put all our phones in the living room at nine every night.
Haruka:That sounds difficult, but I think it's a good rule.
Mr. Smith:At first it was hard, but soon I started to sleep better.
Haruka:I don't want to feel sleepy in class anymore. So I will 5.
Mr. Smith:Good idea. Let's check how you feel next week.
〔注〕*survey＝調査 *screen＝画面 *rule＝決まり went＝goの過去形 put＝putの過去形 made＝makeの過去形 did＝doの過去形 was＝beの過去形 were＝beの過去形
表2 1日のスマートフォンの使用時間と平均睡眠時間
| 使用時間 | 平均睡眠時間 |
|---|---|
| 1時間未満 | 8時間 |
| 1〜2時間 | 7時間30分 |
| 2〜3時間 | 7時間 |
| 3時間より長い | 6時間 |
(4) 下線部の That が指す内容として最も適切なものを選びなさい。
選択肢を選ぶ（並べかえは「答え合わせ」を押す）と、すぐ正解と解説が出る。間違えたら解説を読んで次へ進む。
① 直前の発言
That の直前で、スミス先生は高校生のころの家族の決まりを話しています。
その決まりの内容は？