1、ambitious

有雄心的；有抱负的；有野心的

Chris is so ambitious, so determined to do it all.

克里斯踌躇满志，决心要将它都做完。

He's a very ambitious lad and he wants to play at the highest level.

他是个很有抱负的小伙子，想参加最高水平的比赛。

规模宏大的；艰巨的

The ambitious project was completed in only nine months.

这个规模宏大的项目只用了9个月就完成了。

Their goal was extraordinarily ambitious.

他们的目标极其宏伟。

2、hold back

（使）犹豫;（使）退缩

The administration had several reasons for holding back.

政府因为几个原因而犹豫不决。

Melancholy and mistrust of men hold her back.

忧郁的性格和对男人的不信任使她裹足不前。

阻挡;阻止

Stagnation in home sales is holding back economic recovery.

国内销售的停滞不前正阻碍着经济复苏。

Jake wanted to wake up, but sleep held him back.

杰克想要醒来，但睡意使他又沉入梦乡。

抑制住,忍住(眼泪、笑声等)

She kept trying to hold back her tears.

她一直在试图抑制住眼泪。

He could no longer hold back convulsive laughter.

他再也忍不住，前俯后仰地大笑起来。