If I don't hang this laundry tonight, it will be a problem.

I've been talking about conditional sentences for the past three days:

http://upgradeenglish.blogspot.com/2009/06/if-you-dont-understand-conditional.html
http://upgradeenglish.blogspot.com/2009/06/if-you-dont-get-to-station-before-last.html
http://upgradeenglish.blogspot.com/2009/06/if-you-put-hot-food-in-fridge-you-risk.html

Today, I want to talk about first conditional. We use first conditional to talk about:

• a condition that really might happen sometime in the future
• a real reaction to that possible condition

The grammar for first conditional is often (though not always) like this:

If you learn to use conditional sentences well, <- "if" clause, present tense
it will be useful. <- main clause, "will" + v

You can use it when you are making plans. The definitions below are from 英辞郎 on the web:

If the weather isn't good tomorrow, we'll have to cancel the hiking trip.
If I can find the time, I'll meet you at a cafe.

• find the time to ～する時間｛じかん｝を作り出す・Somehow, she also finds time to do fifty sit-ups every day. : 彼女は毎日どうにか腹筋運動を50回する時間を作り出している。

You can use it when you are making threats:

If your factory makes another mistake, we will stop doing business with you.

• do business 営業｛えいぎょう｝する、商売｛しょうばい｝する、ビジネスを行う、商談｛しょうだん｝する

If you don't treat me better, I'll leave you.

You can use it when you are making promises:

If you give us a good price, we'll definitely choose your factory.
If you help me, I'll help you in return.

• in return 返礼｛へんれい｝［返報｛へんぽう｝・お礼・お返し・見返り］として

Simply, you can use it to talk about one particular future situation:

If I don't go to bed soon, I'll have trouble getting up in the morning. <- true!
If I forget to hang this laundry, it will definitely mildew. <- this time, this particular load of laundry, also true!

• mildew うどん粉菌、白かび、うどん粉病

However, compare that to yesterday's discussion of zero conditional:

If I forget to hang wet laundry, it mildews. <- every time

Tomorrow is my dad's birthday. If I forget to call him, his feelings will be hurt. If I call in the morning, I wonder if he'll be at home or outside having dinner with my mom. Because the people in my family like to talk on the phone, if I call in the morning, maybe I'll be late to my first appointment. If I call him after class though, he'll be on his way to work and won't have time to talk. Hmm... maybe I'll just have to call in the morning for a quick congratulations, and then call again later on the weekend when we both have more time.

In the meantime, I had better go hang that wet laundry. If I don't, it will definitely stink in the morning.

If you don't understand this explanation, I hope you will ask me about it.