請問兩個有關capital和patent的問題 - 經濟

1.What is the opportunity cost of investing in (physical) capital?
Do you think a country can "over-invest" in capital?

真的不太懂..市場均衡的時候應該不會有問題，
他問的又是指哪部份的不均衡造成over-invest
還是哪些主要原因會影響比較大(市場利率偏低?)
2.The patent system is one way through which the goverment can encourage
research. Suppose the government would like to increase the numeber of
years for patent lasts. What would be the effects of this change on
economic growth? Explain the potentially good and bad effects.

這題幾乎完全沒概念...
本來以為跟獨佔市場的獨佔力有關，
獨佔使得P>MR=MC而造成無謂損失
而保護專利權會使得獨佔力更強，進入障礙更大而更難達到社會最適
Explain the potentially good and bad effects.
這句話讓我很冏...

麻煩各位大大幫小弟解惑，謝謝

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