例句： The cold weather will persist for the rest of the week.

例句： I worry about her constantly.

例句： It is obvious that she is very clever.

例句： The death of their daughter was a cruel blow.

例句： Let's evaluate the evidence.

例句： We sampled the stuff and found it satisfactory.

例句： He has natural ability, but has yet to learn the mechanics of his chosen work.

例句： Under his intense gaze she felt uncomfortable.

例句： We must introduce some system into our office routine.

例句： The solar cell can convert the energy of sunlight into electric energy.