英语改句 保持原句意思不变The ice on the river is too thin for us to skat

英语改句 保持原句意思不变
The ice on the river is too thin for us to skate on.
The ice on the river is not _____ _____.
Shops reduce the prices at weekends to attract more custormers.
Shops reduce the prices at weekends _____ _____ they can attract more customers.