do something on the sly (quiet).

leave furtively and stealthily.

偷偷地，悄悄地离开。

To move stealthily or cautiously.

偷偷地或小心翼翼地走

cause to move furtively and hurriedly.

偷偷地并且仓促地移动。

The documents had Been spirited away.

文件被偷偷地带走了

He ran swiftly toward the giant.

他偷偷地冲向了巨人，

He slipped the money into his pocket.

他偷偷地把钱放入口袋。

The cat moved stealthily in on the sparrow.

猫偷偷地向麻雀逼近。

He stole a kiss from her.

他偷偷地吻了她一下。

She ran slyly through the wall.

她偷偷地穿过那堵墙。

To flirt with, especially in secret.

调情调情，尤指偷偷地

Then he would secretly made clay figurines of them inside his sleeves.

他偷偷地在袖口里捏制。

The cat crept with stealthy movements toward the bird.

猫偷偷地接近鸟儿。

Occasionally I took a furtive glance at him.

偶尔我偷偷地望他一眼。

sneak candy into one's mouth; sneaked a look at the grade sheet.

偷偷地把糖塞进嘴巴；偷偷地瞥了一眼成绩单

To peer through a small aperture or from behind something.

偷窥透过细缝或从某物后面偷偷地看

To look or peer furtively, as from a place of concealment.

偷窥如从一个隐秘的地方偷偷地看或凝视

slunk away ashamed; a cat slinking through the grass toward its prey.

羞惭地偷偷溜走了；一只猫偷偷地穿过草丛向猎物扑去

He black-marketed grain on the quiet.

他偷偷地做黑市粮食买卖。