他这个一般是夏天开始营业，因为夏天天热游泳的人比较多

人类和虎鲸有共同祖先？

一种说法就是虎鲸的祖先和原始人类之间的关系就好像现在人类和狗狗的关系，人类和虎鲸之间可能有着共同的祖先，人类有可能起源于大海，因为人类泪液中有0.9%的盐分，所以虎鲸和人类的这种友好关系一直传承到现在。

其实，动物保护者协会在很早以前就呼吁停止鲸鱼表演了，因为鲸鱼是一种大型的海洋生物，平日里过的都是自由散漫的生活，一旦被圈养起来就容易得忧郁症，毕竟再大的游泳池也无法和海洋相比。看似风光无限的虎鲸表演，其实虎鲸背后是要承受痛苦的！

虎鲸和人类的祖先有某种亲密关系。我们知道，古猿在进化成南方古猿时，中间有一段长达三百万年的空白期。这段空白期，陆地上完全没有找到化石，也没有发现遗迹。于是有人猜想，古猿去了海洋里生活，变成了海猿。人体的诸多生理特征和水生动物相似，和其他陆生动物差别较大，海猿假说能解释这一点。

美国推荐100本最佳童书有哪些？

Here is a list of one hundred books selected by the National Education Association as great reading for children and young people. To help make these books more useful, we have added book and author links to any TeachersFirst resources and lesson ideas. For more reading ideas - including books grouped by theme and grade levle - check out the hundreds of titles in our Suggested Reading section.

Books for All Ages

The Giving Tree by Shel Silverstein
Where the Sidewalk Ends: the Poems and Drawing of Shel Silverstein by Shel Silverstein
Little Women by Louisa May Alcott
The Wizard of Oz by L. Frank Baum
Heidi by Johanna Spyri

Books for Preschoolers - More Preschool Titles from TeachersFirst / TeachersAndFamilies

The Very Hungry Caterpillar by Eric Carle
Goodnight Moon by Margaret Wise Brown
Brown Bear, Brown Bear, What do you see? by Bill Martin, Jr.
The Rainbow Fish by Marcus Pfister
Corduroy by Don Freeman
The Snowy Day by Ezra Jack Keats
The Runaway Bunny by Margaret Wise
Guess How Much I Love You by Sam McBratney

Books for Children Ages 4-8 - More Primary Reading from TeachersFirst / TeachersAndFamilies

The Polar Express by Chris Van Allsburg
Green Eggs and Ham by Dr. Seuss
The Cat in the Hat by Dr. Seuss
Where the Wild Things Are by Maurice Sendak
Love You Forever by Robert N. Munsch
Alexander and the Terrible, Horrible, No Good, Very Bad Day by Judith Viorst
The Mitten by Jan Brett
Stellaluna by Janell Cannon
Oh, The Places You'll Go by Dr. Seuss
Strega Nona by Tomie De Paola
The Velveteen Rabbit by Margery Williams
How the Grinch Stole Christmas by Dr. Seuss
The True Story of the Three Little Pigs by Jon Scieszka
Chicka Chicka Boom Boom by John Archambault
The Complete Tales of Winnie the Pooh by A. A. Milne
If You Give a Mouse a Cookie by Laura Joffe Numeroff
The Lorax by Dr. Seuss
Amazing Grace by Mary Hoffman
Jumanji by Chris Van Allsburg
Math Curse by Jon Scieszka
Are You My Mother? by Philip D. Eastman
The Napping House by Audrey Wood
Sylvester and the Magic Pebble by William Steig
The Tale of Peter Rabbit by Beatrix Potter
Horton Hatches the Egg by Dr. Seuss
Basil of Baker Street by Eve Titus
The Little Engine That Could by Watty Piper
Curious George by Hans Augusto Rey
Wilfrid Gordon McDonald Partridge by Mem Fox
Arthur series by Marc Tolon Brown
Lilly's Purple Plastic Purse by Kevin Henkes
The Little House by Virginia Lee Burton
Amelia Bedelia by Peggy Parish
The Art Lesson by Tomie De Paola
Caps for Sale by Esphyr Slobodkina
Clifford, the Big Red Dog by Norman Bridwell
The Paper Bag Princess by Robert N. Munsch

Books for Children Ages 9-12 - More Books by Grade Level from TeachersFirst

Charlotte's Web by E. B. White
Hatchet by Gary Paulsen
The Lion, the Witch, and the Wardrobe by C. S. Lewis
Bridge to Terabithia by Katherine Paterson
Charlie and the Chocolate Factory by Roald Dahl
A Wrinkle in Time by Madeleine L'Engle
Shiloh by Phyllis Reynolds Naylor
Little House on the Prarie by Laura Ingalls Wilder
The Secret Garden by Frances Hodgson Burnett
The Boxcar Children by Gertrude Chandler Warner
Sarah, Plain and Tall by Patricia MacLachlan
The Indian in the Cupboard by Lynne Reid Banks
Island of the Blue Dolphins by Scott O'Dell
Maniac Magee by Jerry Spinelli
The BFG by Roald Dahl
The Giver by Lois Lowry
James and the Giant Peach: A Children's Story by Roald Dahl
Little House in the Big Woods by Laura Ingalls Wilder
Roll of Thunder, Hear My Cry by Mildred D. Taylor
Stone Fox by John Reynolds Gardiner
Number the Stars by Lois Lowry
Mrs. Frisby and the Rats of Nimh by Robert C. O'Brien
The Best Christmas Pageant Ever by Barbara Robinson
Matilda by Roald Dahl
Tales of a Fourth Grade Nothing by Judy Blume
Ramona Quimby, Age 8 by Beverly Cleary
The Trumpet of the Swan by E. B. White
The Chronicles of Narnia by C. S. Lewis
The Phantom Tollbooth by Norton Juster
Tuck Everlasting by Natalie Babbitt
Anne of Green Gables by Lucy Maud Montgomery
The Great Gilly Hopkins by Katherine Paterson
Little House books by Laura Ingalls Wilder - Laura Ingalls Wilder Webquest
Sideways Stories from Wayside School by Louis Sachar
Harriet the Spy by Louise Fitzhugh
A Light in the Attic by Shel Silverstein
Mr. Popper's Penguins by Richard Atwater
My Father's Dragon by Ruth Stiles Gannett
Stuart Little by E. B. White
Walk Two Moons by Sharon Creech
The Witch of Blackbird Pond by Elizabeth George Speare
The Watsons Go to Birmingham-1963 by Christopher Paul Curtis

Books for Young Adults - More Books by Grade Level from TeachersFirst

Where the Red Fern Grows by Wilson Rawls
The Hobbit by J. R. R. Tolkien
Summer of the Monkeys by Wilson Rawls
The Cay by Theodore Taylor
The Sign of the Beaver by Elizabeth George Speare