下列物质中，含有氧分子的是   （）

    Mr. Black takes his daughter 1 a restaurant. They sit down, and there are a lot of  2 in the restaurant. They 3 for a long time, but no waiters come to their table.

    Mr. Black says, "I'm 4, I can't wait." He waits for a minute and says, "Now I am going to 5 something to get a waiter soon."

    He goes out of the restaurant and 6 the restaurant, "My 7is at a table in your restaurant, she 8 a red hat."

    The waiter finds the girl and he says to Mr. Black, "Yes, she's here. Do you want to 9 her?"

    "No," says Mr. Black, "But please give her something to eat quickly. She is very 10". Then he goes back to the restaurant. He is glad to see that a waiter is now at this table.

抛物线$y^2=2px\left(p>0\right)$的焦点为$F$，已知点$A,B$为抛物线上的两个动点，且满足$\angle AFB=120°$.过弦$AB$的中点$M$作抛物线准线的垂线$MN$，垂足为$N$，则$\frac{\left|MN\right|}{\left|AB\right|}$的最大值为 (   )

中国政府首次提出和平共处五项原则是在（   ）