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Read this paragraph: (12) In 1957, two friends invited Jane to visit Africa. (13) Finally, her dream of seeing htese animals was coming true. (14) A few months after she arrived in Africa, she met a famous scientist. (15) His name was Dr. Louis Leakey. (16) Dr. Leakey needed someone smart to help him examine chimps in the wild. (17) After meeting Jane Goodall, he knew that he had found the finest person for the job. (18) In 1960, Jane began to study chimps. (19) Dr. Goodall continued studying them for the next 35 years. The writer would like to add the following sentence to the paragraph. Tell the best place to put the sentence. At first it was difficult for her to be alone with the chimps, but she soon learned to enjoy watching them in the wild.
What is after sentence 18, since this sentence tells about studying the chimps.