The first textbooks ______ for teaching English as a foreign language came out in the 16th century.
The newly-founded company is faced with lots of trouble, ____ the financial problem ia not the worst.
.--- Excuse me, can you tell me the way to the bank?---Oh, that's ____, it's either the second or the third road on the left.
I wonder ____ we can solve this hard problem.
---Would you please give him the paper the moment he ____?--- No problem.
____ is mentioned above, the number of the cattle here has been limited to 200.