The purpose of the study was to explore students' alternative conceptions and their associative thinking regarding internal transport in plants through administration of a refined diagnostic test. Questions of associative thinking and explanation were added to form a third tier of the previous two-tier test. The study found three terms related to alternative conceptions: capillary action, minerals, and nutrients produced by photosynthesis. The students' associative thinking related to these three terms suggested that: (1) capillary action is linked to a hair-water relation, (2) minerals are in the nutrients group, and (3) oxygen is linked to nutrients. Finally, issues regarding the impacts of language on conceptual learning are discussed under three strands: effects of language, Chinese language, and textbook language.