a variety of

• A variety of geological environments are extrusive or intrusive rocks .
  不同的地质环境为喷出岩或侵入岩。
• A variety of geological environments are extrusive or intrusive rocks .
  不同的地质环境形成喷出岩或侵入岩。
• Hence a variety of dilute mineral acids are used to extract the anions .
  因此用各种稀的无机酸来萃取阴离子。
• We have touched upon subjects from a variety of fields of geology .
  我们已经论及了地质学领域中提出的各种问题。
• The temperature of a substance may be changed under a variety of conditions .
  物质的温度可在不同条件下发生变化。
• A variety of conifers and hardwoods makes up the bulk of the vegetation .
  大部分植被由各种针叶树类和阔叶树类构成。
• Real crystals exhibit a variety of departures from this idealized structure .
  真实晶体和这种理想的结构有种种出入。
• They show an inquisitive mind casting about in a variety of directions .
  他们显示了一颗追根问底的心，在向四方探索。
• In this project they were plagued with a variety of mechanical problems .
  在这个设计中，许多机械问题使他们觉得为难。
• Refinery and petrochemical operation produce a variety of byproduct gases .
  炼油厂和石油化工生产中生成各种副产气体。