缩拢你的唇。 稍微卷曲你的舌头。 开始吹气。 通过改变舌头的位置来发出其它的哨声。

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Pretend like you're about to give a kiss, and make your lips into a puckered shape. The opening in your lips should be small and circular. Your breath flowing through this opening will produce a range of notes.   Another way to get your lips in the right position is to say the word "two." Your lips should not be resting against your teeth. Instead, they should be stretched slightly forward. If your lips are quite dry, lick them before you begin whistling. This may help improve the sound you produce. Curl the edges of your tongue slightly upward. As you begin whistling, you'll change the shape of your tongue to produce different notes. For beginners, rest your tongue against your bottom row of teeth. Eventually, you should learn to move the shape of your tongue to form different tones. Blow gently, slightly altering the shape of your lips and the curve of your tongue until you're able to produce a clear note. This may take a few minutes of practice, so don't give up too quickly. It might take a while.  Don't blow hard, just softly at first. You'll be able to whistle more loudly once you find the right form for your lips and tongue to take. Wet your lips again if they dry out while you're practicing. Pay attention to the shape of your mouth when you find a note. In what exact position are your lips and tongue? Once you find the note, keep practicing. Try blowing harder in order to sustain the note. Try pushing it slightly forward to produce higher notes, and lifting it from the bottom of your mouth for lower notes. Play around until you're able to whistle up and down the scale.  To produce lower tones, you'll notice your jaw is lower as well. Producing lower tones requires creating a bigger mouth area. You might even point your chin downward when whistling low notes. Your lips will be slightly tighter when you're producing higher notes. You might lift your head up to whistle a high note. If you're hissing instead of whistling, your tongue might be too close against the roof of your mouth.