Glaucus vainly endeavored to cheer the exhausted spirits of Ione.
格劳科斯徒然地竭力安慰着垂头丧气的伊俄涅。

The disheartened instructor tried vainly to arouse their interest.
沮丧的教师试图激起他们的兴趣，但却是徒劳。

They tried vainly to blame us for the break down in the truce talks.
他们企图把停战谈判的破裂归罪于我们, 但却是徒劳的。

In your despair you wander about vainly seeking contentment in empty pleasure.
绝望中，你浪迹天涯，在虚无的快乐中寻找幸福。

continue vainly trying to achieve sth in spite of several unsuccessful attempts
尽管屡次失败，仍然枉费心机地试图做成某事

While I was still vainly trying to establish order I heard a frightful yelling.
我正在徒劳无功地维持秩序，忽然听到一声可怕的喊叫。

The papal captain have vainly endeavoured to induce his wife to remain behind him.
教廷的队长曾白费力气地试图说服妻子留下不去。

Luan Ping stood still vainly to answer the battery of questions Yang Zirong raised.
栾平 呆立着，回答不出杨子荣得一系列问题。

Smile, the thirteenth momentperhaps, Dream has no end, I wait vainly for you forever.
微笑，第十三个瞬间，梦没有尽头，空待永远。

Before they fled the country, the enemy vainly attempted to destroy all the factories.
敌人在逃往国外前，妄图把所有工厂都毁掉。

Start to read as early as possible, otherwise you will vainly regret it in the future.
读书不趁早，后来徒悔懊。

Humans migrate in search of food and try vainly to live like the animals off the land.
人类为了寻找食物而大迁徙并试图过着动物一样的生活。

To no end gathered vainly then released, forth flowing, wending back loom of the moon.
漫无目的地凑在一起然后又徒然地散开，淌出去，又流回来。

Luyou wrote in the A Long Song:"The warrior's too old to avenge the disgrace of his nation,as the sword at night vainly voices its ambition."
《长歌行》：“国仇未报壮士老，匣中宝剑夜有声”。