税务机关是发票的主管机关，增值税专用发票由国务院税务主管部门指定的企业印制。
参考答案：对
I have sent him messages ________. But he always ignores them.[ ]
A. over again
B. once again
C. over and over again
D. all over
________ a difficult situation, so you should send him a message and give him some advice.
A．As he is in
B．He is in
C．Being in
D．He being in
