1.7 The expression $\frac{2 x^{2}-x}{(x+1)(x-2)}-\frac{4+x}{(x+1)(x-2)}$ cannot be evaluated for $x=-1$ or $x=$ 2, because zero cannot be a divisor. For other values of $x$,
(A) this expression can have many different values.
(B) this expression has only the value 2.
(C) this expression has only the value 1.
(D) this expression has a value between -1 and +2.
(E) this expression has a value greater than 2 or less than -1.
(2nd American High School Mathematics Examination, 1954)
[Solution] Original expression $=\frac{2 x^{2}-x-x-4}{(x+1)(x-2)}=\frac{2(x+1)(x-2)}{(x+1)(x-2)}=2$. Therefore, the correct choice is $(B)$.