29.What do hand-lowering gestures by self-described supporters of gender equality suggest?A.They help defend beliefs.B.They change social attitudes.C.They improve public speaking.D.They may reflect unspoken opinions.30.What do the underlined words "at sea"probably mean in paragraph 4?A.Relaxed.B.Confused.C.Capable.D.Relieved.31.What is the main idea of the book's last section?A.A summary of the book's major research findings.B.Evidence for gestures'role in children's storytelling.C.Hands-on suggestions for caregivers concerning gestures.D.Comparisons of different approaches to children's learning.