Definite, indefinite, and zero articles

Fill the gaps with a / the / - (zero article). Then listen and repeat after the speaker.
1. And house where John Wilkes Booth planned assassination of Abraham Lincoln is actually also now Chinese restaurant called Wok and Roll, on H Street in Washington. ▶2. Shapley realized that if you mapped out these globular clusters, they formed rough sphere. And, more importantly, that most of these clusters were in one part of night sky. ▶3. He figured that middle of sphere corresponded to middle of galaxy, in which case Earth would be far from center of Milky Way. ▶4. So I wrote back saying thanks for heads-up. heads-up is piece of information that's given in advance of something happening or piece of advice. ▶5. I'm professional climber and I just love to be in mountains. ▶6. Mont Blanc massif is kind of birthplace of climbing in Europe. ▶7. Nowhere else in Alps has really, really steep faces and so many technical routes on such small area. ▶