No courage to raise a hand and ask? Lack of opportunity to communicate with teachers? Desire an innovative way of learning?

Roll-Call And Sign-In：only take a few seconds to complete the roll-call
Answer Questions：by question types like multiple-choice, short answer, peer review...etc, gather the opinions and answers of students fast
Learning Record：accessable for answers to questions-- convenient for reviewing after class
Feedback and discussion: enliven thinking with interaction like sending messages to teachers or discuss with classmates in the forum.