People who have investigated the phenomenon have offered many theories to explain human laughter. Scholars in the field of psychology, for example, have done 42 on the subject of what makes people laugh. People who have investigated the phenomenon have offered many theories to explain human laughter. Scholars in the field of psychology, for example, have done research on the subject of what makes people laugh. (A)efforts (B)explanation (C)issues (D)research 調查的現象已經提出了許多理論來解釋人類的笑聲。例如,在心理學領域的學者,做研究的主題是什麼讓人們笑。 (A)努力 (B)解釋 (C)問題 (D)的研究