How to Express Permission and Advice: …てもいい and …方がいい

Last time, you learned how to express prohibition and obligation, e.g. “宿しゅく題だいを忘わすれてはいけない (You must not forget your homework),” and ”復ふく習しゅうをしないといけない (You have to review [it]).” Then, if you would like to say, “You don’t have to do your homework,” or “It’s better for you to do your homework,” what should you do? In this lesson, you will learn how to express permission and advice.

Explanation for How to Express Permission and Advice

Permission means actions that you are allowed to do, while advice means actions that you are suggested to do. Permission and advice can be given to not only people whom you're talking with, but yourself and the public. Let’s check how it works.

Permission: …てもいい

You can express permission by attaching もいい to the te-form. In conversation, it will sound more natural if you place the sentence ending particle よ. The いい (of てもいい) means “good” and thus you can replace いい with other words which have the similar meaning such as “大だい丈じょう夫ぶ: alright” and “構かまわない: no problem.” Here, we will use いい because that’s the most common.

If you make interrogative sentences with てもいい, it means that you ask permission. You can also indirectly ask permission by using てはいけない (prohibition) like “Is it prohibited to do X?” In general, てもいい is more commonly used.

If you make negative sentences with てもいい, it means to permit you to not do something. In other words, it is unnecessary to do something. The conjugation is the same as the one for なくては (prohibition), but you replace ては with てもいい.

Japanese people sometimes drop も from てもいい, but the meaning will remain the same.

てもいい can be used to express your volition with a passive attitude. The nuance will be something like “I don’t want to do it, but if you request me, I can do it.” In this context, も cannot be dropped.

Advice: …方ほうがいい

This is the sentence pattern that you learned in the previous lesson about comparison. This essentially means “it is better to do X [than not to do X],” and may be translated as “should” in English. Regarding the conjugation, you can just connect the ta-form with 方がいい. The sentence ending particle よ also takes an important role here, which makes sentences softer.

If you would like to place the より part, you can directly connect the plain form of verbs to より.

With this sentence pattern, tense is a little tricky. First, if you conjugate いい into the past tense, i.e. よかった, you can express actions which you didn't take with regretful feelings like “I should have done it.”

Second, you can actually connect the plain form with 方が, too. That way, your speech will sound like a general opinion rather than advice to the individual. Note: this is not a common expression. When you give advice, you should use the ta-form.

Third, if you give advice with negative sentences, you have to use the plain-negative form.

Summary

1. …てもいい expresses permission and can be translated as “can” or “may.”
2. …なくてもいい expresses unnecessary actions and can be translated as “don’t have to.”
3. …方がいい expresses advice and can be translated “better to do” or “should.”
4. …方がよかった expresses advice with regretful feelings like “should have done.”
5. With affirmative sentences, the ta-form with 方が is common.
6. With negative sentences, the plain-negative form with 方が is common.

Great job! You have completed the modality (speaker’s feeling) section. Now, you are able to express various feelings in Japanese, which will greatly change your speech to be more colorful. If you feel difficulty in conjugating verbs, we recommend you review the previous lessons before moving to the next section. As you may notice, some forms, such as the polite form and the te-form, can be a base for various conjugations. Then, we have showed examples so far on the promise that there is no conjunction. Next, you will learn how to form compound sentences.