couldn't help but do 表示容易、方便做……；不能不……；不得不……；不禁……；情不自禁……；忍不住要……；立刻……；
The pistol was positioned where I couldn't help but see it...
I couldn't help but notice the pointed remarks slung in my direction
We couldn't help but admire it.
I couldn't help but wonder, what is this about?
I couldn't help but laugh out gently.
I couldn't help but stare, but it's her inner beauty that you really feel.
I couldn't help but see, pretty woman, that you look lovely as can be.
It hurt so much that I couldn't help but cry out in pain.
When he fell into the pond I couldn't help but burst out laughing.
I had never seen my father cry, and when I heard this, I couldn't help but start to cry myself.
我从未看见我父亲哭过，当我听到这些的时候，我禁不住哭出声来。Arriving in Beijing, I couldn't help but notice the ads and signs
三、have no choice but to do和can't choose but do 与couldn't choose but do和can't choose but do something
have no choice but to do和can't choose but do 两种表达方式都没问题。只是语法现象不同。前者的but to do是不定式，做choice的定语，而后者的but do是与choose并列的谓语。
couldn't choose but do
can't choose but do something
强调“别无选择”，此时可以说与can’t help but 完全同义，如“我不能不感到遗憾”就可以用不同的手段表示——
I cannot choose but be sorry.（除了遗憾别无选择）
I cannot help but be sorry. （除了遗憾只能无可奈何）