苦笑的英文：
forced smile

参考例句：

Hung-chien, with a rueful smile, had no choice but to take the child
鸿渐无可奈何，苦笑接过来。

Gradually a wry smile settled on his face.
一丝苦笑浮现在他脸上。

The old man smiled sadly when he remembered the follies of his youth
这老人想起年轻时的荒唐事，不禁苦笑。

Fan Po-wen, looking ill at ease, shrugged his shoulders and gave a hollow laugh
范博文耸耸肩膀苦笑，是非常为难的样子。

After what seemed like hours he came out with a wry smile.
好像过了好几个小时，他终于出来了，脸上挂着苦笑。

While I dialyzed, Dave shuffled in wearing a grin
在我接受血液透析治疗时，戴夫拖着脚步走进来，面带着苦笑。

Lord Mountdrago smiled, but the smile that tried to be careless was only rueful
芒德内哥勋爵笑了笑，他原想表现得若无其事，结果却露出了一副苦笑。

forced是什么意思：
adj. 被迫的，强迫的
v. force的过去式和过去分词；强迫

by (main) force
用蛮力, 全靠气力; 以最大的力气

The force is spectacular!
这个瀑布很壮观！

resultant force
合力

The threat will force greater dispersion of their forces.
恫吓将迫使他们把兵力铺得更广。

The tension force, shear forces (including pushing force, cutting force and friction force), impulse force, hydrodynamic drag on the suction pipes, and the force resulted from the pressure difference, etc, are the main forces for detail discussion in this paper.
详细讨论了主要作用力：在波浪补偿器作用下的缆绳拉力、耙头与海床间的土壤剪切力、作用在耙吸管上的水流阻力及由于压力差在耙头处产生的推动力等。

smile是什么意思：
v. 微笑，笑；惠及，露出（笑容）
n. 微笑；笑容

He smiled a discreet smile.
他的脸上露出带思虑的微笑。

a responsive smile
表示回答的微笑

What are you smiling at?
你笑什么?

A man may smile and smile and be villain
笑里藏奸

face melt in smiles; all smiles; beam with satisfaction
眉开眼笑