Read the passage below and choose the best answer for each question.
Miss Richards was a teacher at a school in England. She taught chemistry and physics from the lowest to the highest classes in the school. Sometimes the new classes learnt quickly , but sometimes they were very slow, and then Miss Richards had to repeat things many times. One year , the first class had studied chemistry for several weeks when Miss Richards suddenly asked : “ What is water?” . There was a silence for a few seconds, and Miss Richards felt sad , but then one of the boys raised his hand. He was not one of the most intelligent students in the class, so she was glad that he could answer “ Water is a liquid which has no colour until you wash your hands in it,” the boy replied.
The word “ repeat” in this passage means _________ .
A.explain
B.say again
C.study more
D.reuse