2. In a game, a sector with a radius of $1 \mathrm{~cm}$ represents a “monster,” as shown by the shaded area in the figure. The central angle of the缺口 part (i.e., the monster's mouth) is $60^{\circ}$. What is the perimeter of this “monster” (i.e., the sector)?
(A) $\pi+2$;
(B) $2 \pi$;
(C) $\frac{5}{3} \pi_{3}$
(D) $\frac{5}{6} \pi+2$;
(E) $\frac{5}{3} \pi+2$.
2. The central angle of the shaded sector is $300^{\circ}$, so the required perimeter is $\frac{5}{6}(2 \pi r)+2 r=\frac{5}{3} \pi+2$.
(E) True.