Questions 18 to 20 are based on the following passage. At the end of the passage, you will be given 15 seconds to answer the questions. Now listen to the passage. What implication of the research is the speaker concerned about

A．Language acquisition may be negatively affected.
B．Babies used in experiments often develop emotional problems.
C．Parents may force their children to learn at too early an age.
D．Early coaching will interfere with creativity.