121、It is necessary for you to do sth.是你有必要做某事。

165、He had made significant to logic, mathematics and quantum mechanics.

164、A thousand fifty digit numbers could in the storage unit.

163、The sand surface was used earlier for writing had evolved into a hoard with lines.

162、The calculation aid used by human being was abacus.

161、 this in view, English for science should be properly taught and learnt.

160、There is a high degree of correlation mathematics and computer science.

159、office automation system

158、electronic mail

157、desktop computer

156、application software