详解
Choice A is the best answer because it most accurately describes the function of the underlined sentence in the text as a whole. The first sentence of the text indicates that Johnson returned to the US in 1938 at which time his painting style suddenly changed. The second sentence is underlined and gives more detail about this stylistic change, noting that his earlier work consisted largely of landscapes in an expressionist style and his new works were highly stylized portraits of Black Americans. In other words, the function of the underlined sentence is to elaborate on a transitional moment in Johnson’s painting career.
Choice B is incorrect. Although the text does mention that Johnson spent a decade in Europe, it does not discuss what other travel Johnson might have done. Furthermore, although the text mentions African, American, and Scandinavian artistic elements in Johnson’s work, it does not indicate that he traveled to different locations to learn about these practices. Choice C is incorrect because the text does not focus on Johnson’s personal life nor does it address how successful his career was in general. Choice D is incorrect because, rather than call it into question, the underlined sentence continues the discussion of Johnson’s career by adding further relevant detail of Johnson’s artistic transformation.