1. Guests arrived singly or in groups. 客人有单个来的,也有三三两两一起到的。
2. They marched out singly or in pairs. 他们一个一个地或成双成对地走出去。
3. The stamps are available singly or in books of ten. 邮票有单枚的,也有十枚一册的。
4. Good separation of co-ions and counter ions cannot be achieved by a single type of the singly charged NF membranes. 采用单一的荷电纳滤膜是不能实现同名离子和反荷离子之间的高效分离的。
5. They can be used singly or as a pair. 它们可以单独使用或作为一对。