Most spacecraft are still at little risk of collision with space debris during their operational lifetimes, but given the numbers of new satellites launched each year, the orbital environment in the future is likely to be less (i) __________
Blank (i) |
(A) crowded |
(B) invulnerable |
(C) protected |
(D) polluted |
(E) benign |
정답은 benign 입니다.
혹시 B invulnerable은 왜 안되는지요..?
둘 다 안전하다라는 뜻이 있는 것 같아서요.