It is necessary to examine this claim（ ）we proceed any furtherbefore until when since 2.his work( ),he left his office with joy.A finished B being finished C finishing D was finished应该选哪个？

it is necessary for you to work Is it necessary to learn grammer It is necessary for sb to It is necessary to do 的例句 it is necessary for you to remember some usefui words and e 关于necessary.it is necessary to do sth.it is nec关于necessary. it is necessary to do sth. it is necessary to doing sth. 两者有什么区别?什么时候用to do .什么时候用 to doing?请回答, Change is not necessary to life,it is life it is clear that sleeping is necessary to everyone is it necessary to tell his father everything?此句用is that necessary 英语necessary的问题It is necessary for us to learn.可不可以改成We are necessary to learn The indoor swimming pool seems to be a great deal more luxurious than ( )A is necessary ;B being necessary ;C to be necessary ;D it is necessary It is necessary to protect trees from the frost.翻译 It is necessary to protect trees from the frost. It is necessary ( ) travellers to take a map when is it necessary to pass cet4 or cet6 in uiniversity It is necessary for you to take an X-ray. Why is it necessary to encourage a low carbon lifestyle? It is necessary for me to have some help 翻译