If a stone thrown int

Question

If a stone thrown into a pond, the ripples will spread out from

the point where the stone hits the water.
請問為什麼這句的thrown 文法不對呢？如何改才對呢？

Answer 1

在 if .....的句子中 若後面那句是用未來式
前面的if.....句就要用現在式

so the correct answer is : If a stone throws into a pond, the ripples will spread out from the point where the stone hits the water.