______, many problems of space flight could not be solved now.A．If electronic computers wo

Many a problem has ______ because of poor planning.A．arisenB．risenC．raisedD．aroused

The process of urbanization has caused many problems, the major one is ______.A．economyB．t

Violence is just one of the many problems ______ in city life.A．abundantB．inherentC．substa

The ______ newspaper accounts of the marital problems of the royal couple fascinated many

In space,______and equipment need many forms of protection.A．pilotsB．astronautsC．engineers

Seldom did we realize that many of our hair problems______what we eat.A．rely onB．refer toC