1."Half this number is less than 6 times the tens dight of the number by 4."
数值的一半比它的十位数值的6陪小于4.
2.For general exploringobjects requirement, narrow pulse signal with tens millimicro second to millimicrosecond has the frequency spectrum from DC to thousands MHz.
3.Overpumping groundwater for drinking water and irrigation has caused water levels to decline by tens of metres in many regions, forcing people to use low-quality water for drinking.