All the members of the WTO should follow the ______ of trust and fair(公平) trade.
People have planted a great many trees in order to ________ wind and sand in the desert.
Traditionally, Chinese people _______ the Chinese characters Double Happiness and stick them onto walls or doors for weddings.
.People like taking photos because photos are the _______ of youth and history and can remind us of many happy scenes.
A much better way must be found to achieve an equal ________ of the resources.
Unfortunately, the element Madam Curie devoted all her life her death.