3. the whole form of the second word the first part of the first word helipad: helicopter pad 直升飞机升降场 medicaid: medical t aid 美国的医疗补助方案 medicare. medical care 医疗照顾方案helipad: helicopter + pad 直升飞机升降场 medicaid: medical + aid 美国的医疗补助方案 medicare: medical + care 医疗照顾方案 3. the whole form of the second word + the first part of the first word: