高一課程免費學(xué)習(xí)網(wǎng)

　　[答]by 在此表示“到(某時)為止”或“到某時”已發(fā)生某事或出現(xiàn)某種情況，謂語動詞多用完成時態(tài)。句中的1840是過去時間，因此謂語動詞用過去完成時had come, 又如：

　　By the end of last year we had produced 3000 computers. 到去年年底為止我們已生產(chǎn)出3000臺電腦。

　　She had finished her work by the time I came home. 我回家時他已干完活了。

　　By next week we will have made a plan for our journey. 下周前我們會訂出旅行計劃。

　　9. Since the mid-1980s growing numbers of Asians have settled in New Zealand, and they make up about 6% of the total population. 自從80年代中期以來，定居在新西蘭的亞洲人數(shù)不斷增加，他們占新西蘭總?cè)丝诘?%。