英语介词的用法详解(精华篇)

1、Thecompass

Acompassisasimpleinstrumentforjudgingdirections.Thepredecessorissinan.Themaincomponentisamagneticneedlemountedonashaftthatcanrotatefreely.

Undertheactionofthegeomagneticfield,themagneticneedlecanstayinthetangentialdirectionofthemagneticmeridian.

TheNorthPoleofthemagneticneedlepointstothegeographicNorthPole,whichcanbeusedtoidentifydirections.

Commonlyusedinnavigation,geodesy,travelandmilitary,etc.Nfornorth,Eforeast,Wforwest,Sforcompass.

2、Paper-making

PapermakingisoneofChina'sfourgreatinventionsandanoutstandinginventioninthehistoryofhumancivilization.Chinawasthefirstcountryintheworldtoraisesilkwormsandweavesilk.

InancientChina,thesilkcocoonsoftheworkingpeopleandabovewereusedtodrawsilkandweavesilk.Afterfinishingthefloc,thebamboomatwillbeleftsomeresidualfloc.

Whenthenumberofdriftflocmore,bamboomatontheresidualflocwillbeaccumulatedintoalayerofthinfiber,afterdryingoff,canbeusedforwriting.

Thisflocculantfloatingtherearen'tmanyby-products,andcallith蹏onancientbookorsideeffect.ThisshowsthattheoriginofChinesepapermakingiscloselyrelatedtosilkfloc.

3、Gunpowder

Ablackorbrownexplosive,mechanicallymixedwithpotassiumnitrate,charcoal,andsulfur,initiallyinpowderformandlateringranulesofdifferentsizes,fordifferentpurposes,

untiltheuseofsmokelessgunpowder,hasbeenusedastheonlymilitarypropellant.

4、Theprintingpress

TheearliestengravingfoundsofarisasinglepageversionofthedouronisutrainIndianSanskrit,printedonlinenpaper,publishedbetween650and670yearsago,andunearthedinatangdynastytombnearxi'anin1974.

In1966,archaeologistsinSouthKoreadiscoveredaminiatureversionofthedolonibuddhistsutra,whichcontainedthetextofthezurenscriptissuedbyempresswuzetianofthetangdynasty(C.690-705).

Scholarsdeterminedthatthesutradidnotdatebackto704andwaslaterpreservedinastupabuiltduringtheunificationofsillain751.

However,theearliestknownprintedbookofanaveragesizewasthediamondsutrapublishedduringthetangdynasty(618-907).

Thescroll,whichis5.18meters(17feet)longandinscrollformat,datesbacktoApril15(868),theninthlunarmonthofemperoryizong'sreign.

TheaccountsofscholarsJosephNeedhamandTsientsuen-hsuinshowthatthecalligraphyandcarvingtechniquesofthetangdynastydiamondsutrawerefarmoreadvancedandsophisticatedthanthesingle-pageIndianversionofthedolonisutra,

whichwasprintedearlier.Inaddition,thetwooldestprintedlunarcalendardatesare877and882,whentheywerediscoveredindunhuang.