Because oil is likely to become more costly in the future, natural rubber looks an attractive alternative from an economic point of view as well as an engineering one.
石油在未来可能更加昂贵，所以，从经济及工程角度来看，天然橡胶似乎是不错的选择。
2
Habasit offered the M5020 POM dark grey as an alternative to the rubber belts.
哈伯斯特提供替代的橡胶带M5020甲醛深灰色。
3
As an alternative, the upper and lower members may be brought together, and rubber material may be injected into position to have a tread formed thereon.