45. One can guess from the passage that Samuel Clemens... A) was very careful of getting to learn every peculiarity of the river.
B) was too ambitious to become a steamboat pilot.
C) was a nickname of Mark Twain.
D) after 18 months apprenticeship changed his name for Mark Twain.
46. We learnt from the passage that Twain’s most famous book... A) was written in 1857 to realize his old ambition.
B) reflects the actual author’s knowledge of the river geography.
C) had no direct relation to Samuel Clemens’s own life.
D) is about efforts to learn languages during the next four years after apprenticeship.