Little empirical research has been conducted on what effect task-based reading instruction with reading questions will have on reading comprehension, particularly in the domain of second language reading comprehension. The purpose of this research is to investigate which type of questions, textually explicit (TE) or inferential (IF) questions, will best facilitate text comprehension, and which type will have the most beneficial effect on Japanese EFL learners at three proficiency levels (low, intermediate, and high). In the study, two groups of Japanese senior high school students (N = 69) were classified into three different proficiency groups. One group received instruction emphasizing TE questions while the other received instruction emphasizing IF questions. TE questions are text-bound questions whose answers are locally and explicitly stated in the text. In contrast, IF questions are more knowledge-bound questions whose answers largely depend on readers' cognitive resources, such as relevant linguistic knowledge, background knowledge, world knowledge or context. The different treatments lasted five months. The results were statistically analyzed. The study revealed a significant task effect for reading questions on Japanese EFL learners' reading. Although one type of instruction did not have a significantly better effect than the other, the large between-groups gain gap seems to imply that instruction emphasizing IF questions might facilitate text comprehension more. The study also found that the participants who received instruction emphasizing IF questions benefited from their instruction regardless of proficiency level. With regard to instruction emphasizing TE questions, the higher proficiency participants benefited significantly more from their instruction than the lower proficiency students. The study suggests that reading teachers should use a task-based teaching method with reading questions. If the use of reading questions is already a part of reading teachers' methodology, they should include not only commonly used textually explicit reading questions but also inferential ones. The study suggests that implementing these changes might help break the cycle of translation-bound reading instruction with its overemphasis on lower-level processing, and might lead students to read texts in a more meaningful, interactive way. / CITE/Language Arts