他被认为是可持续发展理念的主要倡导者之一。

He is regarded as one of the leading ___exponents of sustainable development.

在表达式5的4次方中，4是指数。

In the expression 5 to the 4th power, 4 is the ___exponent.

作为现代艺术的杰出代表，她举办了许多创新展览。

As a leading ___exponent of modern art, she has organized many innovative exhibitions.