各位大神，这是我们英语考试选择题，跪求答案

c1.Childrengetparents______Christmasand______theirbirthdays.(固定搭配）

A.on,atB.in,atC.at,onD.by,on

D2.Theytalked______lowvoicesinordernottobeheard.

A.atB.byC.onD.in

B3.Shewas______hertwentieswhenshewentabroad.

A.atB.inC.forD.of

A4.Therearemanybirdssinging______thetrees.

A.inB.onC.atD.with

C5.Mikereceivedanaward______hisoutstandingresultsintheexams.

A.toB.aboutC.forD.with

D6.Tomlosthisway,______delayedhimconsiderably.

A.thatB.whenC.whereD.which

D7.Ifhe______hereIcouldexplaintohimmyself.

A.isB.hasbeenC.wereD.was

A8.Thedistrictgrewpeas______alargescale.

A.onB.inC.byD.to

C9.I’mgoingtoParis______mybrotheriscomingaswell.

A.bothB.orC.eitherD.and

A10.Thetimehascome______wecanmakeextensiveuseofnuclearenergy.

A.asB.whenC.whileD.since

D11.Thebossmay______Tonybecausehehastherightqualifications.

A.fireB.fineC.dismissD.hire

A12.Heknewnothingaboutthisjourney______hewaslikelytobeawayforthreemonths.

A.thatB.exceptthatC.howeverD.inaddition

B13.Whattime______forwork?

A.areyouusuallyleavingB.doyouusuallyleave

C.youusuallyleaveD.youusuallyleft

A14.______younervousduringtheinterview?

A.WereB.DidC.DoD.Had