单项选择题 The crankshafts on the large modern 2-stroke crosshead engines are （）big （）makes as a single unit and so are constructed by joining together individual forgings.

单项选择题 Because the tie bolts are so close to the crankshaft, some engines employ （）to hold the crankshaft main bearing cap in position instead of conventional studs and nuts.

单项选择题 To prevent excessive （） in the transverse girders, the tie bolts are positioned as close to the center of the crankshaft as possible.