All the contributors were of African descent.

所有捐助者都是非洲血统。

All the contributors are credited on the title page.

所有撰稿人的姓名均刊登在扉页上。

Older people are important contributors to the economy.

老一辈人为发展经济作出了重要贡献。

Old buses are major contributors to pollution in cities.

旧公交车是造成城市污染的主要原因。

Editors and contributors are trying to second-guess the future.

编辑们和投稿者们正在试图预测未来。