88. be on a diet/be dieting: 节食 They find it hard to exercise while they are on a diet. 他们发现节食期很难进行锻炼。
89. be out of control/lose control of/get out of control: 失控 反义：under control India’s human population has grown out of control. 印度的人口增长已经失控。
90. be indispensable to: 必不可少的，不可或缺的 Interpersonal relationships are indispensable to people's social well-being. 人际关系对人们的社交圈子而言是不可或缺的。
91. be concerned with: 考虑；关于，涉及 Fashion designers are rarely concerned with vital things like warmth, comfort and durability. 时装设计师很少考虑到保暖，舒适，耐用这类重点。 The book concerns itself with/is concerned with the effects of pollution on health. 这本书讲的是污染对健康的影响。 concern n.关心，关切 Excessive concern with safety can be dangerous. 过度关注安全是危险的。
