「どうやって○○」は英語で何？「how」の使い方

Some people in class the other day were asking about how to use "how". Here's the advice I gave them. "How" has at least three meanings when used in a question.

• How do I do it? "how" = "way", どうやって..., answer with a method, as in "Do it this way."
• How does he feel? "how" = どのよう..., answer with an adjective, as in "It feels great!"
• How cold was it? "how" = どのくらい...[how + adj/adv]... answer with an adverb, as in "It was very cold."

The money tree is doing really badly. It was so dense back in November, but not now. How do I prevent it from dying?

• prevent ~ from 〔主語は〕～が…するのを防ぐ［邪魔｛じゃま｝する］、～に…させない、～が…できないようにする、～が…にならないように予防｛よぼう｝する、〔主語が原因｛げんいん｝で〕～は…できない (definition from Eijiro on the Web)

There were five trunks. Three of them died. There are two left, and those two don't look so good. How bad do you think it is?

• trunk〔木の〕幹 (definition from Eijiro on the Web)

I wonder how the money tree feels. Maybe it's just feeling too cold. We tried changing the pot, but that didn't seem to help. How long can it survive? I hope it can make it until spring. Maybe it will start growing better once the weather is warmer.