[ 1只带线网球[另送1根弹力绳] ]

[ 2只带线网球[另送1根弹力绳] ]

[ 3只带线网球[另送1根弹力绳] ]

[ 5只带线网球[另送1根弹力绳] ]

[ 网球训练器 ]

[ 训练器+1只带线球[送1弹力绳] ]

[ 训练器+2只带线球[送1弹力绳] ]

[ 训练器+3只带线球[送1弹力绳] ]

[ 训练器+5只带线球[送1弹力绳] ]

[ 弹力绳3根 ]