They've promised to keep both we quality and the quantity of the 300 bicycles in conformity with the contract stipulations.
他们已承诺那300辆自行车的质量和数量一定与合同规定相吻合。
Fortunately, however, ancient men made tools of stone, especially flint,
然而, 幸运的是,远古人用石头制作了工具,特别是用燧石,