In the following words, which underlined（下划线的）letters have a different sound from the others?

Which pair of the words with the underlined letters has the same sound?

Which of the following words doesn’t have the same stress（重音）as the others?

—What do you want to do this weekend?

—I want to care for animals in ________ animal center.

—________ have you been in Beijing?

—For two weeks. And I went to the Great Wall.