题目

① ② ③ ④ ⑤ ⑥ ⑦ ⑧ 答案：① −12+3−5+6 = −12−5+3+6 = −8 ② (−32)÷8×(−4) = 32÷8×4 = 16 ③ 5−(−2.5)+(−0.5)−3 = 5+2.5−0.5−3 = 4 ④ (−2)×(−32)÷(−34) = −2×32×43 = −4 ⑤ 1+(13−14−16)×(−48) = 1+13×(−48)−14×(−48)−16×(−48) = 1-13×48+14×48+16×48 = 1-16+12+8 = 5 ⑥ (−1)8+8÷(−2)3−(−4)×(−3) = 1+8÷(−8)−12 = 1−1−12 = −12 ⑦ −215×(13−12)�为了联系方便，在两个办公室各装了一只电铃，要使任何一方按开关都只能使对方的电铃发声，则如图所示的电路图中正确的是A.B.C.D.