1.A
1）across是個介詞,swim across the river“游過那條河流”；
2）meaure 100 meters wide在此處做后置定語,修飾the river.
而measure作為“長度/寬度為...”時是不及物動詞,表明the river和measure之間是主動關系,所以只能使用其現(xiàn)在分詞measuring.
2.C
固定句型“How did it come/bring about that-從句?”意思是“.是怎么發(fā)生的?”
come back “回來”無此句型；
“it occur to sb that-從句”意思是“某人突然想起/想到...”；
get down “下來/使...下來”無此句型.