hadwitnessedhad been buriedhad been本讲栏目开关语法感知知识储备Period SixPeriod Sixhad diedupgradedrepairedservicedreplaced本讲栏目开关语法感知知识储备Period SixThe film had begunThe students had left the classroomWe hadnt thought of thathave my hair cutget my tyres pumped up本讲栏目开关语法感知知识储备Period Six本讲栏目开关语法感知知识储备Period Six本讲栏目开关语法感知知识储备Period Six本讲栏目开关语法感知知识储备Period Six本讲栏目开关语法感知知识储备Period Six本讲栏目开关语法感知知识储备Period Sixhad lefthad taughthad intendedhadlefthadspokenhad served本讲栏目开关语法感知知识储备Period Six本讲栏目开关语法感知知识储备Period Six本讲栏目开关语法感知知识储备Period Six本讲栏目开关语法感知知识储备Period Sixmendedburningtakenworkrepair本讲栏目开关语法感知知识储备