Social Sciences. In short, a two-mode is a hybrid vehicle that can operate in two distinct ways (modes). The first mode works much like a regular full hybrid. It is the second mode that makes the difference--where the hybrid system can adjust varying amounts of engine and motor function to meet very specific vehicle/task/traffic requirements.
Twain's first book, The Innocents Abroad, was published in 1869, The Adventures of Tom Sawyer in 1876, and The Adventures of Huckleberry Finn in 1885. He wrote 28 books and numerous short stories, letters and sketches. Mark Twain passed away on April 21, 1910, but has a following still today.
The series was an instant success: by mid-1929 over 115,000 books had been sold, and as of 2008 the books were selling over a million copies a year (the first Hardy Boys book, The Tower Treasure, alone sells over 100,000 copies a year). Worldwide, over 70 million copies of Hardy Books have been sold.