TAs are indispensable for first-year programming education offered at universities. The problem of students who cannot ask questions due to their inability to be proactive has become a major problem in online lectures due to the impact of COVID-19. In addition, the control of waiting for questions and responding to questions, as well as the mental stress of whether the TA will be able to respond to questions, can also be major problems. In this study, we propose and implement a method in which students do not ask questions directly to the TAs, but ask questions to the system, and the TAs check the questions in advance and call the TAs when they are available. Our method can lower the barrier for students to ask questions, and also reduce the mental load of TAs. We have used our method for a total of 1600 minutes in an actual online lecture and obtained high evaluations from students and TAs.