Problem: (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: "Which two players did Roger Federer lose to in consecutive Wimbledon Semifinals matches?"

Answer: "The passage doesn't talk about Federer losing in semifinal matches"
Answer: no

Problem: Sometimes traits can vary from parent to offspring. These changes are due to mutations. Mutations are a random change. Mutations are natural. Some mutations are harmful. In this case, the organism may not live to reproduce. The trait will not be passed onto offspring. Others variations in traits have no effect on survival. Can some mutations be good for a living thing? Other mutations can have great benefits. Imagine being the first moth that can blend into its background. It would have a better chance of survival. A living thing that survives is likely to have offspring. If it does, it may pass the new trait on to its offspring. Thats good news for the offspring. The offspring may be more likely to survive. Mutations are one way living things adapt to new conditions.

Question: "Are mutations always harmful?"

Answer: "Yes"
Answer: no

Problem: A stranger in town meets pretty young Susan Martinez De La Cruz and accompanies her to a barbecue , where wealthy Jason Carberry is saying a few words for the recently departed Robin Randall , a citizen who got shot . Jason objects to the stranger's presence , being Susan's guardian and protective of her . He challenges him to a shootout , but the stranger pulls his pistol before Jason's can even clear the holster . Calaveras Kate , a saloon singer who's in love with Jason , is relieved when the stranger declines to pull the trigger . Rafael Moreno suddenly rides into town and picks a fight with the stranger . Their brawl continues until the arrival of Judge Wallace Wintrop and his niece , Sheila , who have come to town from back East and deplore all this random violence out West . The stranger is recognized as Reb Randall , the dead man's brother . He is looking for the killer , who could be Rafael , or could be Jason , or could even be Billy Buckett , the coward of the county . The women hold their breath to see if the men they love will survive .

Question: "Is Billy Bucket the killer?"

Answer: "Only in speculation"
Answer:
yes