改错题，根据内容找出错误并改正错误。.E7u2v9Q;i2N3x8Z4i*z
A teacher could make classes lively and ,y/I6f6^+B8F'K)G;h____7^+^.f)e'r+Sinterested. Once he asked his class to watch 0W*[:w*v6l4n8j*U6q,f;p3@*w____9o(d6k3[/[7D carefully first and then do everything he do. 2E2t6Z:h1v/o6s6`4U-f;{8k'R'F____-{9D:~*o0D4i'Q3X9f2_,f0D-K+_ He held up one of his finger and dipped it 'A.V;H3^4r(X)e(k,H;q(I____+b9g5w4x7T;\5l*d'p into a cup in a mixture. Then he took it 1}/^7K,^;A____,P0V)Q8x4[6z1m out the cup and put a finger in his mouth the cup of and sucked it with smile. Then he told smile athe students to do again. Each student made a +[9Z5@9@-}*E;^'s7X/h,L(|4o____6i2r.]*i7U4U face after he did that the teacher had done. 5~(^9?4P7u4y5T7X'o2m1M2y;Y____*M(s1p7|4?2F3u.X9S;k Finally he saw none of them watched carefully. The finger he sucked was not the one he had dipped into the cup..E7u2v9Q;i2N3x8Z4i*z