The fourth part 'the system of force majeure in Anglo-American law ( system)', explains frustration of contract and force majeure clause in Anglo-American law ( system) assume jointly the part function of the system of force majeure. 第四章是英国法上不可抗力制度,该部分说明了合同落空制度与不可抗力条款共同承担不可抗力制度的部分功能。