题目

_______ from heart trouble for years, Professor White has to take some medicine with him wherever he goes. A. Suffered     B. Suffering        C. Having suffered  D. Being suffered 答案：C请在下面的数字后面填上适当的单位：（1）一枚1元硬币的质量大约为6_______（2）氧气的密度约为1.43_________（3）一瓶“雪碧”的体积大约为1.25________（4）一名中学生质量50__________