In this task, you're given an article and an answer. Your task is to generate the fill-in-the-blank question for this answer based on the given article. The blanks are always at the end of the question, and can be filled with more than one word or phrase.

Article: Many people have wondered what makes the oceans rise and fall on the word's beaches twice a day. Those tides are caused by the force of the Moon's gravity and the rotation of the Earth. Gravity acts on the center of any solid object. The Earth is mostly molten rock, but compared to the oceans, we can think of it as a solid object. As you know, the oceans are fluid and lie on the surface of the Earth. When the Moon is overhead, the oceans are four thousand miles closer to the Moon than the Earth's center is. Because the oceans are closer, the Moon pulls harder on the water than on the Earth. This stronger pull makes the water bunch up a little under the Moon, creating a high tide. At the same time, the oceans on the opposite side of the Earth are four thousand miles farther from the Moon than the Earth's center is. The Moon's pull on this water is weak. This water bunches up because it is "left behind"(making another high tide) as the Earth is pulled slightly towards the Moon. When the waters bunch up on these two sides of the Earth, they draw water away from the other sides of the Earth, which creates the low tides. As the Earth rotates, different parts of the land and oceans pass through the high-tide and low-tide zones. And that makes the waters on our coasts go up and down.
Answer: Moon's gravity or Earth rotation
According to the passage, there would be no tides if there were no _ .

Article: "Beauty is only skin deep." This expression means that beauty is only a temporary surface quality. Some beauty products can cause lasting damage that goes far below the surface of the skin. In America,many people use sunlight and non-natural light to darken their skin. Health experts advise against what is called"tanning"because of its links to akin cancer. In the African country of Senegal ,some women take health risks trying to do just the opposite. An average beauty supply shop in Dakar has many kinds of skin-lightening creams and soaps. The World Health Organization says that 25%of Senegalese women use skin-lightening production a usual basis. These products can contain chemicals,like mercury ,hydroquinone ,etc. These are dangerous ingredients that can cause cancer and possibly other physical damage to the akin. They can actually burn the eyes and skin. Shop worker Adama Diagne advises her visitors to avoid the stronger products that promise fast results. She users a cream that is made from carrots,not the strong chemical,hydroquinone. She says that it is a personal choice and that no one pressures her. Some women want to be black every day,but for her,she likes to be a shade of brown. Women in Senegal say they lighten their skin for the same reason that women all over the world make changes to their appearance. They say they want to look beautiful,to find a husband, to stand out in a crowd or simply to look great for a special event. This thinking troubles Senegalese film-maker Khardiata Pouye Sall. So,she made"This Color That Bothers Me",a film about the subject of skin lightening. She said,"I used the most shocking images so that women would see the dangers. It is hard to understand why a woman says that dark skin is not beautiful. It is in their heads. They want to please a man,to he loved or they want to please society,to succeed." Ms. Sall says that the government needs to better control the marketing and the sale of skin-lightening products. But she adds that education is the best way to persuade people against using them.
Answer: a product can make you beautiful quickly
According to Adama Diagne,women shouldn't believe _ *

Article: My school has no cafeteria . Students bring their own lunches and eat in the classroom with their teachers. At first, I didn't think I needed to be "on" during lunch, since it was technically a free time for students. However, I was surprised to learn that even in a classroom with fewer students, social segregation happened. The entire class crowded around a table just to avoid one or two other students sitting by themselves on the other side of the room. Students refer to one as the "cool" one and another as the "loser". There were only three tables. After witnessing this, I made a new classroom rule. Every day at lunch, we would put all the tables together and everyone including me would sit around the big table. Students could sit wherever they wanted at the table. This way, no one was excluded from the group. At first, there was much grumbling at this. But gradually the complaining stopped. Students who didn't usually talk to each other during free time started to share conversations. Students were occasionally requested to bring something for others to taste. This started a new tradition: weekly food sharing. In other situations, students make unpleasant comments about their classmate's food, but not during these lunches. Students were careful to thank the sharer, even if they didn't like the offering. Many students tried a food they had never tried before and some cooked a family recipe with their parents for the first time. Eating together gave us the opportunity to practice social graces . Students learned to ask about and respect each other's food choices. They also gained knowledge about their classmates' lives and cultures by tasting each other's food and practicing open-mindedness.
Answer: needed to eat with other teachers
At the beginning, the author didn't eat in the classroom with his students because he _ .