●Software designis a (66) process.It requires acertain (67) of flair on the partof the designer.Design can not be learned from a book.It must be practiced and learnt by experienceand study of existing systems.A well (68) software system is straightforward to implementand maintain，easily (69) and reliable.Badly (68) software systems，although theymay work are (70) to be expensive to maintain，difficult to test and unreliable. (66) A．create B．created C．creating D．creative (67) A．amount B．amounted C．mount D．mounted (68) A．design B．designed C．designing D．designs (69) A．understand B．understands C．understanding D．understood (70) A．like B．likely C．unlike D．unlikely