Which word has the underlined part pronounced differently from that of the others?

This is a family with five members.

Mike: We're looking for a talented artist for the music program next month.

Sarah: My friend Anna, _______ sings folk songs very well, may be suitable.

Harry: When do the Vietnamese celebrate their Independence Day?

 Lan: They celebrate it _______ September 2^nd.

David: Which natural ______ usually occurs in the United States?

Nancy: Tornados quite often strike the nation.

Thomas: What is the weather like in Ho Chi Minh city in summer?

Tai Nguyen: It's often hot. The temperatures are normally ______ 29⁰C and 38⁰C.

Mark: What do you think about your Chemistry teacher?

Helen: He's great. He always _______ his students to do their best.