按合同

• ex contract
• by contract
• on contract

例句

1. 如合同一方不按合同条款行事，另一方则有权中止合同。
   If one side failed to honor the contract, the other side should be entitled to cancel it.
2. 该公司没有按合同中规定的日期付款。
   The company fails to pay on the date stipulate in the contract.