高手帮忙解下几道关于English时态的题.
1.thediscoveryofgoldinAustralialedthousandstobelievethatafortune____(make).
2.Alan,makesurethetables_____(set)beforetheguestsarrived.
3.Bobwouldhavehelpedusyesterday,buthe_____(busy).
4InthespokenEnglishhofsomeareasintheUS,the‘’r''soundsattheendofthewords____(drop).
5Thiscoastalarea_____(name)anationalwildlifereservelastyear.