Going on a trip into         space must be quite         exciting experience.

/; the 

/; an

the; the 

the; an

考查冠词。句意：太空旅行是令人兴奋的经历。第一空不填，space前面不加冠词，第二空后面的experience作“经历”时是可数名词，表示“一次令人兴奋的经历"。exciting首字母的发音为元音音素，因此应填an。故选B项。

As a matter of fact,           beauty of           nature there made an excellent impression on me.

a; the; /

a; the; the

the; the; /

a; /; the

考察冠词。句意：事实上，那里的自然之美给我留下了极好的印象。as a matter of fact “ 事实上”，为固定短语。第二个空表示特指，用定冠词the。Nature表示“大自然，自然界”时，前面一般不加冠词。故选A项。

I would really appreciate       if you can make time in your schedules to attend my lecture today.

that

it

this

one

考查形式宾语。句意：如果你今天能从日程安排中抽出时间来听我的讲座的话，我将不胜感激。I would appreciate it if/when...如果/当...时，我将非常感激。it 做形式宾语。故选B项。