When the teacher ______ how to do the experiment, the bell rang.
)What’s thatEnglish? A、at B、on C、in
)—What’s this? —It’sorange. A、a B、an C、the
)—What color is your pen? —It’s. A、black B、a blue C、a yellow pencil
)—Are the keys yellow? —. A、Yes, it is B、No, they aren’t C、Yes, she is
)Look! Heremy English books. A、is B、are C、am