过路的人经过一盏路灯下时，灯光照射人所形成的影子长度的变化是______．

小题1:The government has taken action. Now there is _______pollution in the river.

小题2:Sandy is planning to hold a party to celebrate her father’s _________birthday.

小题3:I was happy that I finished my job __________.

小题4:Millie’s grandparents live in a flat not far from _________, she can often see them.

小题5:Peter and Judy keep in touch by ___________ emails.