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。
Why does aperson standing in a bus or train tend to fall when a sudden start is made?
一个人站在公共汽车或火车上,当车突然开动时,他为什么会倾倒呢?