unable to help however much one would like to (idiom) / Although we sympathize, there is no way to help you. / My hands are tied.
强中自有强中手
qiáng zhōng zì yǒu qiáng zhōng shǒu
however strong you are, there is always someone stronger (idiom) / there is always sth more to learn / never be satisfied to rest on your laurels / there is no room for complacency
每一个人都有美中不足的地方
měi yī gè rén dōu yǒu měi zhōng bù zú de dì fang
However excellent, everyone has his defects. / There is always a fly in the ointment. / cf idiom 美中不足[mei3 zhong1 bu4 zu2], everything is fine except for one small defect
牡丹虽好，全仗绿叶扶
mǔ dan suī hǎo , quán zhàng lu:4 yè fú
Although the peony is beautiful, it depends entirely on help from the green leaves (idiom). However brilliant you may be, you can't do anything without support from others.
牡丹虽好，全凭绿叶扶持
mǔ dan suī hǎo , quán píng lu:4 yè fú chí
Although the peony is beautiful, it depends entirely on help from the green leaves (idiom). However brilliant you may be, you can't do anything without support from others.
牡丹虽好，全仗绿叶扶持
mǔ dan suī hǎo , quán zhàng lu:4 yè fú chí
Although the peony is beautiful, it depends entirely on help from the green leaves (idiom). However brilliant you may be, you can't do anything without support from others.
牡丹虽好，终须绿叶扶持
mǔ dan suī hǎo , zhōng xū lu:4 yè fú chí
Although the peony is beautiful, it depends entirely on help from the green leaves (idiom). However brilliant you may be, you can't do anything without support from others.
山外有山，天外有天
shān wài yǒu shān , tiān wài yǒu tiān
(idiom) however good sth is, there is always sth better / in the wider world there are people more talented than oneself
bù guò