A:he was able to make himself hear
B:he was able to make himself heard
C:was he able to make himself hear
D:was he able to make himself heard
“星系”级别的天体系统是( )
①太阳系 ②地月系 ③河外星系 ④银河系 ⑤总星系.
用科学计算器计算:8+3sin56°≈____ (精确到0.01)