(CNN) -- Jo-Wilfried Tsonga ended Roger Federer's hopes of winning a record-equaling seventh Wimbledon title on Wednesday as the French 12th seed staged a stunning fightback to reach the semifinals. Federer appeared to be cruising into the last four after winning the first two sets, but Tsonga inflicted the Swiss world No. 3's first defeat from that vantage point in 179 grand slam matches. It was only the third time in the 29-year-old's glittering career that the 16-time grand slam champion had surrendered a two-set lead. Tsonga, ranked 19th in the world, triumphed 3-6 6-7 (3-7) 6-4 6-4 6-4 on Centre Court, serving out to love as he earned a clash with second seed Novak Djokovic. The Serbian, who beat Tsonga in the 2008 Australian Open final, ended the dream run of Australian 18-year-old Bernard Tomic. Tsonga defeated Federer for just the second time in six meetings, their first on grass. "It was amazing. I played unbelievable. It's never easy to come back against Roger. I'm so happy, it's crazy," the 26-year-old told reporters after reaching the semifinals at Wimbledon for the first time. "He's the biggest champion in the sport. He has achieved so much and is the best player in the world. To be two sets down and come back was unbelievable. I served really well. Against Djokovic I will have to come out and do the same again." Federer has now lost in the quarterfinals two years in a row, being beaten by eventual runner-up Tomas Berdych in 2010. "Jo played great. Really from start to finish I don't remember seeing a break point after I broke him in the first game," Federer said.

Question: "Who was the tennis player that lost to Jo-Wilfried Tsonga?"

Response: "Roger Federer"
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A: yes

Callimaco is taken by the beauty of Lucrezia , but she is the loyal wife of Nicia , a rich and foolish lawyer . Callimaco hires the service of a shady ' fixer ' named Ligurio to aid in his quest to sleep with her . Lgurio informs Callimaco that Nicia and Lucrezia are anxious to have a child . With the fixer's help , . Callimaco masquerades as a doctor and convinces Nicia that the best way for Lucrezia to conceive a child is by her taking a potion made from the Mandrake Root . He lies and warns Nicia that the first man to sleep with Lucrezia after she has taken the potion will die within eight days . Together they devise a plan to kidnap a stranger to sleep with Lucrezia and draw out the poison . Callimaco then disguises himself and arranges to be the one who is kidnapped . Lucrezia is an honorable woman and does not at first agree to meet with the stranger . Nicia gets both Lucrezia's mother , a woman of ill repute , and her confessor Brother Timoteo , a priest of low morals , to aid in convincing Lucrezia of the necessity of the plan . After finally sleeping with Lucrezia , Callimaco confesses everything . Lucrezia gives thought to the duplicity of her husband , her mother , and her confessor , and decides that she now wants Callimaco as a lover forever . Callimaco gets what he had desired and everyone else continues to believe that each had outwitted the others .

Question: "What potion is believed to be about to kill Lucrezia?"

Response: "Nicia is told that the first man to sleep with her after taking mandrake root potion will die"
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A: yes

Static electricity is like a teeter-totter. What happens if a teeter-totter is balanced? Correct! It does not move. What about when its not balanced? Yes, it will now begin to move. Charges move when they are not balanced. Charges can build up by friction. Maybe you rub your feet on a wool mat or carpet. Rubber soled shoes readily gain charges. The wool carpet easily gives up charges. The two items become unbalanced. One item has a positive charge. The other has a negative charge. The difference in charge is called static electricity. Just like the teeter-totter, something is going to move. Positive charges build up on the mat. Negative charges build up on you.

Question: "What happens if a teeter-totter is balanced?"

Response: "It doesn't move"
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A:
yes