chúfēi kàn gēcí, fǒuzé wǒ búhuì chàng.

It is a very common pattern meaning unless ..., otherwise ....

So in this sentence:

• 除非看歌词
• 否则我不会唱

the structure is:

• 除非 + condition
• 否则 + result if that condition is not met

A natural English equivalent is:

• Unless I look at the lyrics, I won’t be able to sing.
• literally: Unless [I] look at the lyrics, otherwise I won’t sing / won’t be able to sing.

In Chinese, 除非 introduces the only condition under which something can happen.

The subject is understood from the second clause: 我不会唱.

So even though the first part only says 看歌词, it is naturally understood as:

• 除非我看歌词，否则我不会唱。

Chinese often omits subjects when they are obvious from context. Since the second half clearly has 我, listeners automatically understand that the same 我 also applies to 看歌词.

This kind of omission is very normal in Chinese and often sounds more natural than repeating the subject.

Yes, absolutely.

Both are correct:

• 除非看歌词，否则我不会唱。
• 除非我看歌词，否则我不会唱。

The version with 我 is more explicit. The version without 我 is more concise and natural when the subject is already clear.

So the difference is not really about grammar correctness, but about how much you want to spell out.

否则 means otherwise / if not.

In this sentence, it introduces the result that happens if the 除非 condition is not met.

So:

• 除非看歌词 = unless I look at the lyrics
• 否则我不会唱 = otherwise I won’t be able to sing

In many cases, 否则 can be omitted and the sentence still works:

• 除非看歌词，我不会唱。

That is still understandable and grammatical. But adding 否则 makes the logic clearer and more formal or complete.

So:

• with 否则 → clearer, more explicit
• without 否则 → shorter, still natural in many contexts

This is an important question, because 会, 能, and 可以 are often confusing for learners.

Here, 不会唱 usually means I don’t know how to sing it / I’m not able to sing it from memory.

It suggests a lack of ability or know-how in this situation.

Compare:

• 不会唱 = I can’t sing it / I don’t know how to sing it
• 不能唱 = I’m not allowed to sing it, or I’m unable to sing it due to some restriction
• 不可以唱 = I may not sing it / it’s not permitted

In this sentence, the speaker means that without looking at the lyrics, they do not know the words well enough to sing. So 不会唱 fits best.

A very natural interpretation is:

• Unless I look at the lyrics, I won’t be able to sing it.

This is due to a tone change rule.

Normally, 不 is fourth tone: bù.

But when 不 comes before another fourth-tone syllable, it changes to second tone: bú.

Since 会 is fourth tone (huì), we get:

• 不 + 会 → búhuì

Other examples:

• 不是 → búshì
• 不要 → búyào
• 不对 → búduì

So the written form stays 不, but the pronunciation changes.

唱 means to sing.

In this sentence, the object is omitted because it is understood from context. The speaker probably means:

• sing the song
• sing the lyrics
• sing it

So 我不会唱 can mean:

• I can’t sing it
• I don’t know how to sing it

Chinese often leaves out objects when they are obvious.

A fuller version could be:

• 除非看歌词，否则我不会唱这首歌。
  • Unless I look at the lyrics, I won’t be able to sing this song.

But if everyone already knows which song is being discussed, simply saying 唱 is perfectly natural.

Not exactly.

They can sometimes lead to similar English translations, but the logic is a little different.

如果不

means if ... not

Example:

• 如果不看歌词，我就不会唱。
• If I don’t look at the lyrics, then I can’t sing.

This simply states a condition.

除非

means unless / only if

Example:

• 除非看歌词，否则我不会唱。
• Unless I look at the lyrics, otherwise I won’t be able to sing.

This stresses that looking at the lyrics is the only way the speaker can sing.

So 除非 is stronger and more exclusive than 如果不.

The sentence follows a very typical Chinese pattern:

• condition first
• result second

So:

• 除非看歌词 = condition
• 否则我不会唱 = result

Chinese very often puts background, time, conditions, or context before the main statement.

That is why this order feels natural:

• 除非看歌词，否则我不会唱。

If you translate too literally into English, it may sound stiff. A more natural English rendering would be:

• I won’t be able to sing unless I look at the lyrics.

So the Chinese order is normal, even though English often prefers to put the main clause first.

It is mostly neutral.

• 除非 is a normal word used in both speech and writing.
• 否则 can sound a little more explicit or slightly more written than just leaving it out, but it is still perfectly normal in speech.

So this sentence does not sound strange or overly formal. However, in casual conversation, people might say shorter versions such as:

• 不看歌词我不会唱。
• 我得看歌词，不然不会唱。

These are a bit more conversational.

So:

• 除非……否则…… = clear, standard, slightly more structured
• 不然 versions = often more casual in speech

Yes, in many everyday situations you can.

For example:

• 除非看歌词，不然我不会唱。

This is understandable and natural in conversation.

Difference:

• 否则 = otherwise; slightly more formal or standard
• 不然 = otherwise; often more conversational

Both work, but 否则 matches the textbook-style 除非……否则…… pattern especially well.

So if you are learning the grammar pattern, 否则 is the best partner to remember with 除非.