11. （ ）

(单选题)A suitable title for this passage would be ______. (单选题)The scouts shake snow from evergreen bushes in order to ____ (单选题)According to the author, recent work on snow-blindness shows (单选题)The first paragraph is mainly concerned with ______. (单选题)Why did Wild Bill Hickok shoot holes in a hat? (单选题)From this passage, we know that Wild Bill Hickok was not ___ (单选题)The feature that most distinguished Wild Bill Hickok was his (单选题)（ ） (单选题)Water, food and air are ______ great importance ______ human (单选题)To be ______, they need to consider the future and deal with