It’s ____ difficult problem for the twins that ____ of them can work it out .
----The number of the tigers is getting __________. ---- I agree _______ you.
The reserve is an important ______ area for the rare red-crowned cranes.
You should speak as loudly as you can _____everyone hear you clearly
I think ____necessary for us _____the birds.
_____ good time we had in the park yesterday!