If the painting Mona Lisa is on your list of things to see, __________ sure to get there early as there will probably be a line.
He was sitting on the floor ________ by books.
The weather turned out to be fine yesterday. I ________ the trouble to carry my umbrella with me.
My father may have to go into hospital,________ he won't be going on holiday.
Teenagers who discover they were ________ often search for their biological parents when they are old enough.
It was the first time that Zhang Lin had spoken before hundreds of strangers and he spent several days __________ his lecture before he stepped onto the platform.