阅读：网络利与弊 — 英语填空题

阅读下面的观点句，判断其说的是网络的“利”（advantage）还是“弊”（disadvantage），并将合适的词填入空格："Students can search for learning materials online at any time, which is a major ___ of the Internet, but spending too many hours online may harm their eyesight, which is a ___ of it."