His collegues were surprised at his absurd behaviour.

同事们对他那荒诞的行为感到吃惊。

His duties devolved upon his collegues while he were abroad.

他在出国期间他的工作被移交给他的同事。

Lastly, I must say I owe all the achievements to the encouragement and help from my collegues and friends.

最后,我必须说我的这些成就都应归功于我的同事和朋友们的鼓励和帮助。