助動詞に過去動詞を付けないこと

Yesterday the weather forecast I saw didn't predict rain. It was a nasty shock when I looked out the window and saw heavy rain falling, especially since my helmet was hanging on my bicycle and filling up with water.

Today I was a bit wary when I looked at the sky and saw the clouds. I put my rain suit in my bag, but of course, since I brought it, it hasn't rained.

There's a weird basic English rule: don't use a past tense verb after an auxiliary verb.

• auxiliary verb《文法》助動詞｛じょどうし｝表現パターンauxiliary ［helping］ verb

Instead, use present perfect tense after an auxiliary verb to express the past.

× I should brought my rain suit yesterday, too.
○ I should have brought my rain suit yesterday, too.

× Maybe if I had brought my rain suit, it wouldn't rained.
○ Maybe if I had brought my rain suit, it wouldn't have rained.

I wonder if I can cause the typhoon to stay away by keeping my rain suit in bag for the rest of the week.