the drug has had immediate effect on patient 前面的为什么是has 而后面的

this medicine has had no effect on the patient为什么要加 had,has The poor boy had difficulty walking为什么前面是has而后面用walking 根据首字母提示填词The drug has an immediate e______________ on the pa The patient has ____to the drug and is recovering quickly the medicine has had no effect on me 这句话是完成时态吗? 英语翻译The car has also had a significant effect on the culture The patient has ____to the drug and is recovering quickly.re what effect has the booming economy had on interest rates fo 求助英语语法达人The effect globalisation has had on culture is immen The medicine has side effect.为什么? money really has its most useful effect on the poor. Decribe and explain the effect that galvanised steel has on