In the southwest, the climate is pleasantly warm during the winter

不可以，这句话中pleasantly是副词，warm是形容词。
修饰形容词应该用副词

举例，It is warm and pleasant today.

你只可以分开说，去掉不可以

pleasantly是副词，用来修饰形容词，不能去掉，去掉就是形容词了

这句话貌似是我学习的<英语国家概况>里面的...晕
warm是形容词,这里不适合形容词修饰形容词.这里是系+副词修饰形容词形成一个谓语~!